1 | /**************************************************************************** |
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2 | |
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3 | THIS SOFTWARE IS NOT COPYRIGHTED |
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4 | |
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5 | HP offers the following for use in the public domain. HP makes no |
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6 | warranty with regard to the software or it's performance and the |
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7 | user accepts the software "AS IS" with all faults. |
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8 | |
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9 | HP DISCLAIMS ANY WARRANTIES, EXPRESS OR IMPLIED, WITH REGARD |
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10 | TO THIS SOFTWARE INCLUDING BUT NOT LIMITED TO THE WARRANTIES |
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11 | OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. |
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12 | |
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13 | ****************************************************************************/ |
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14 | |
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15 | /**************************************************************************** |
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16 | * Header: remcom.c,v 1.34 91/03/09 12:29:49 glenne Exp $ |
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17 | * |
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18 | * Module name: remcom.c $ |
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19 | * Revision: 1.34 $ |
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20 | * Date: 91/03/09 12:29:49 $ |
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21 | * Contributor: Lake Stevens Instrument Division$ |
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22 | * |
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23 | * Description: low level support for gdb debugger. $ |
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24 | * |
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25 | * Considerations: only works on target hardware $ |
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26 | * |
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27 | * Written by: Glenn Engel $ |
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28 | * ModuleState: Experimental $ |
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29 | * |
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30 | * NOTES: See Below $ |
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31 | * |
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32 | * Heavily modified for XStormy16 by Mark Salter, Red Hat. |
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33 | * Optimisations and 'X' support by Geoff Keating, Red Hat. |
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34 | * |
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35 | * To enable debugger support, two things need to happen. One, a |
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36 | * call to set_debug_traps() is necessary in order to allow any breakpoints |
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37 | * or error conditions to be properly intercepted and reported to gdb. |
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38 | * Two, a breakpoint needs to be generated to begin communication. This |
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39 | * is most easily accomplished by a call to breakpoint(). Breakpoint() |
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40 | * simulates a breakpoint by executing a trap #1. |
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41 | * |
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42 | * Because gdb will sometimes write to the stack area to execute function |
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43 | * calls, this program cannot rely on using the inferior stack so it uses |
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44 | * it's own stack area. |
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45 | * |
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46 | ************* |
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47 | * |
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48 | * The following gdb commands are supported: |
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49 | * |
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50 | * command function Return value |
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51 | * |
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52 | * g return the value of the CPU registers hex data or ENN |
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53 | * G set the value of the CPU registers OK or ENN |
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54 | * |
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55 | * mAA..AA,LLLL Read LLLL bytes at address AA..AA hex data or ENN |
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56 | * MAA..AA,LLLL: Write LLLL bytes at address AA.AA OK or ENN |
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57 | * XAA..AA,LLLL: Write LLLL binary bytes at address OK or ENN |
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58 | * AA..AA |
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59 | * |
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60 | * c Resume at current address SNN ( signal NN) |
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61 | * cAA..AA Continue at address AA..AA SNN |
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62 | * |
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63 | * s Step one instruction SNN |
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64 | * sAA..AA Step one instruction from AA..AA SNN |
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65 | * |
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66 | * k kill |
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67 | * |
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68 | * ? What was the last sigval ? SNN (signal NN) |
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69 | * |
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70 | * All commands and responses are sent with a packet which includes a |
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71 | * checksum. A packet consists of |
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72 | * |
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73 | * $<packet info>#<checksum>. |
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74 | * |
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75 | * where |
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76 | * <packet info> :: <characters representing the command or response> |
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77 | * <checksum> :: <two hex digits computed as modulo 256 sum of <packetinfo>> |
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78 | * |
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79 | * When a packet is received, it is first acknowledged with either '+' or '-'. |
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80 | * '+' indicates a successful transfer. '-' indicates a failed transfer. |
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81 | * |
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82 | * Example: |
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83 | * |
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84 | * Host: Reply: |
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85 | * $m0,10#2a +$00010203040506070809101112131415#42 |
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86 | * |
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87 | ****************************************************************************/ |
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88 | |
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89 | /* Local functions: |
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90 | */ |
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91 | static void putDebugChar(unsigned ch); |
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92 | static unsigned char getDebugChar(void); |
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93 | static void putPacket(unsigned char *); |
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94 | static void putHex (char c, unsigned long mem_arg, int count); |
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95 | static unsigned char *getpacket(void); |
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96 | static void hex2mem(unsigned char *, unsigned long, int); |
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97 | static int valid_addr_range (unsigned long mem, int count); |
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98 | static int hexToInt(unsigned char **, long *); |
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99 | static void prepare_to_step(void); |
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100 | static void finish_from_step(void); |
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101 | |
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102 | /* breakpoint opcode */ |
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103 | #define BREAKPOINT_OPCODE 0x0006 |
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104 | |
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105 | /* Error Detection Register */ |
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106 | #define ERR_DETECT_REG (*(volatile unsigned *)0x7f08) |
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107 | #define UNDEF_INSN_ENA 0x01 |
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108 | #define UNDEF_INSN_FLAG 0x02 |
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109 | #define ODD_ADDR_ENA 0x04 |
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110 | #define ODD_ADDR_FLAG 0x08 |
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111 | #define BAD_ADDR_ENA 0x10 |
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112 | #define BAD_ADDR_FLAG 0x20 |
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113 | #define SER0_IRQ_ENA 0x1000 |
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114 | #define SER0_IRQ_FLAG 0x2000 |
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115 | |
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116 | /***************************************************************************** |
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117 | * BUFMAX defines the maximum number of characters in inbound/outbound buffers |
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118 | * at least NUMREGBYTES*2 are needed for register packets |
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119 | */ |
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120 | #define BUFMAX 80 |
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121 | |
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122 | static const unsigned char hexchars[]="0123456789abcdef"; |
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123 | |
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124 | #define NUMREGS 17 |
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125 | |
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126 | /* Number of bytes of registers (extra 2 bytes is for 4 byte PC). */ |
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127 | #define NUMREGBYTES ((NUMREGS * 2) + 2) |
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128 | enum regnames { R0, R1, R2, R3, R4, R5, R6, R7, |
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129 | R8, R9, R10, R11, R12, R13, R14, R15, |
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130 | PC }; |
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131 | |
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132 | #define FP R13 |
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133 | #define PSW R14 |
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134 | #define SP R15 |
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135 | |
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136 | struct regs { |
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137 | int r[16]; |
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138 | long pc; |
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139 | } registers; |
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140 | |
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141 | static struct regs orig_registers; |
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142 | |
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143 | static unsigned char remcomBuffer[BUFMAX]; |
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144 | |
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145 | /* Indicate whether inferior is running. Used to decide whether or not to |
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146 | send T packet when stub is entered. */ |
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147 | static char is_running; |
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148 | |
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149 | static inline unsigned char |
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150 | get_char(unsigned long addr) |
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151 | { |
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152 | unsigned int msw, lsw; |
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153 | unsigned char ret; |
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154 | |
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155 | msw = addr >> 16; |
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156 | lsw = addr & 0xffff; |
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157 | |
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158 | asm("movf.b %0,(%2)\n" |
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159 | : "=e"(ret) : "d"(msw), "r"(lsw) : "memory"); |
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160 | |
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161 | return ret; |
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162 | } |
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163 | |
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164 | static inline void |
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165 | set_char(unsigned long addr, unsigned int val) |
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166 | { |
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167 | unsigned int msw, lsw; |
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168 | |
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169 | msw = addr >> 16; |
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170 | lsw = addr & 0xffff; |
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171 | |
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172 | asm("movf.b (%1),%2\n" |
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173 | : /* none */ : "d"(msw), "r"(lsw), "e"(val) : "memory" ); |
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174 | } |
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175 | |
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176 | static inline unsigned int |
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177 | get_word(unsigned long addr) |
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178 | { |
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179 | unsigned int ret, msw, lsw; |
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180 | |
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181 | msw = addr >> 16; |
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182 | lsw = addr & 0xffff; |
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183 | |
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184 | asm("movf.w %0,(%2)\n" |
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185 | : "=e"(ret) : "d"(msw), "r"(lsw) : "memory" ); |
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186 | |
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187 | return ret; |
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188 | } |
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189 | |
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190 | static inline void |
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191 | set_word(unsigned long addr, unsigned int val) |
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192 | { |
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193 | unsigned int msw, lsw; |
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194 | |
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195 | msw = addr >> 16; |
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196 | lsw = addr & 0xffff; |
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197 | |
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198 | asm("movf.w (%1),%2\n" |
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199 | : /* none */ : "d"(msw), "r"(lsw), "e"(val) : "memory" ); |
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200 | } |
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201 | |
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202 | static void |
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203 | assign_regs (struct regs *dest, const struct regs *src) |
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204 | { |
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205 | int i; |
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206 | char *d = (char *)dest, *s = (char *)src; |
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207 | for (i = 0; i < sizeof (struct regs); i++) |
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208 | *d++ = *s++; |
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209 | } |
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210 | |
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211 | /* Write out a register for a 'T' packet. */ |
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212 | |
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213 | static unsigned char * |
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214 | putreg (unsigned char *buf, int regnum, void *mem_p, int count) |
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215 | { |
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216 | int i; |
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217 | unsigned char ch; |
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218 | char *mem = (char *)mem_p; |
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219 | |
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220 | *buf++ = hexchars[regnum >> 4]; |
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221 | *buf++ = hexchars[regnum % 16]; |
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222 | *buf++ = ':'; |
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223 | |
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224 | for (i=0;i<count;i++) |
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225 | { |
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226 | ch = *mem++; |
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227 | *buf++ = hexchars[ch >> 4]; |
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228 | *buf++ = hexchars[ch % 16]; |
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229 | } |
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230 | *buf++ = ';'; |
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231 | return(buf); |
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232 | } |
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233 | |
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234 | /* |
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235 | * This function does all command procesing for interfacing to gdb. |
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236 | */ |
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237 | void |
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238 | handle_exception(void) |
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239 | { |
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240 | char sigval; |
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241 | unsigned char *ptr; |
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242 | long addr, length; |
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243 | |
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244 | /* reply to host that an exception has occurred */ |
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245 | sigval = 5; /* SIGTRAP is default */ |
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246 | if (ERR_DETECT_REG & UNDEF_INSN_FLAG) |
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247 | { |
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248 | ERR_DETECT_REG &= ~UNDEF_INSN_FLAG; |
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249 | registers.pc -= 2; |
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250 | if (get_word(registers.pc) != BREAKPOINT_OPCODE) |
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251 | sigval = 4; /* SIGILL */ |
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252 | } |
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253 | if (ERR_DETECT_REG & BAD_ADDR_FLAG) |
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254 | { |
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255 | ERR_DETECT_REG &= ~BAD_ADDR_FLAG; |
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256 | sigval = 11; /* SIGSEGV */ |
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257 | } |
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258 | if (ERR_DETECT_REG & SER0_IRQ_FLAG) |
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259 | { |
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260 | unsigned char ch; |
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261 | |
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262 | ch = getDebugChar(); |
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263 | ERR_DETECT_REG &= ~SER0_IRQ_FLAG; |
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264 | if (ch != 0x03) |
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265 | return; |
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266 | sigval = 2; /* SIGINT */ |
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267 | } |
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268 | |
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269 | finish_from_step(); |
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270 | |
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271 | /* save original context so it can be restored as a result of |
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272 | a kill packet. */ |
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273 | if (orig_registers.pc == 0L) |
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274 | assign_regs (&orig_registers, ®isters); |
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275 | |
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276 | if (is_running) |
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277 | { |
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278 | ptr = remcomBuffer; |
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279 | |
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280 | *ptr++ = 'T'; /* notify gdb with signo, PC, FP and SP */ |
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281 | *ptr++ = hexchars[sigval >> 4]; |
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282 | *ptr++ = hexchars[sigval & 0xf]; |
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283 | |
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284 | ptr = putreg (ptr, PC, ®isters.pc, 4); |
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285 | ptr = putreg (ptr, FP, ®isters.r[FP], 2); |
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286 | ptr = putreg (ptr, SP, ®isters.r[SP], 2); |
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287 | |
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288 | *ptr++ = 0; |
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289 | |
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290 | putPacket(remcomBuffer); |
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291 | } |
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292 | |
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293 | while (1) { |
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294 | char kind; |
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295 | |
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296 | ptr = getpacket(); |
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297 | kind = *ptr++; |
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298 | if (kind == 'M' || kind == 'X') |
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299 | { |
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300 | /* MAA..AA,LLLL: Write LLLL bytes at address AA.AA return OK */ |
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301 | /* TRY TO READ '%x,%x:'. IF SUCCEED, SET PTR = 0 */ |
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302 | if (hexToInt(&ptr,&addr) |
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303 | && *(ptr++) == ',' |
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304 | && hexToInt(&ptr,&length) |
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305 | && *(ptr++) == ':') |
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306 | { |
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307 | if (valid_addr_range (addr, length)) |
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308 | { |
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309 | if (kind == 'M') |
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310 | hex2mem(ptr, addr, length); |
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311 | else |
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312 | { |
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313 | int i; |
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314 | for (i = 0; i < length; i++) |
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315 | if (*ptr++ == 0x7d) |
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316 | set_char (addr++, *ptr++ ^ 0x20); |
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317 | else |
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318 | set_char (addr++, ptr[-1]); |
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319 | |
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320 | } |
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321 | putPacket ("OK"); |
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322 | } |
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323 | else |
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324 | putPacket ("E03"); |
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325 | } |
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326 | else |
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327 | putPacket ("E02"); |
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328 | } |
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329 | else if (kind == 'm') |
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330 | { |
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331 | /* mAA..AA,LLLL Read LLLL bytes at address AA..AA */ |
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332 | /* TRY TO READ %x,%x. IF SUCCEED, SET PTR = 0 */ |
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333 | if (hexToInt(&ptr,&addr) |
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334 | && *(ptr++) == ',' |
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335 | && hexToInt (&ptr,&length)) |
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336 | { |
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337 | if (valid_addr_range (addr, length)) |
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338 | putHex (0, addr, length); |
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339 | else |
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340 | putPacket ("E03"); |
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341 | } |
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342 | else |
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343 | putPacket ("E02"); |
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344 | } |
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345 | else if (kind == 'R') |
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346 | { |
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347 | if (hexToInt (&ptr, &addr)) |
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348 | registers.pc = addr; |
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349 | putPacket ("OK"); |
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350 | } |
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351 | else if (kind == '!') |
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352 | putPacket ("OK"); |
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353 | else if (kind == '?') |
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354 | putHex ('S', (unsigned long)(unsigned int)&sigval, 1); |
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355 | else if (kind == 'g') |
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356 | putHex (0, (unsigned long)(unsigned int)®isters, NUMREGBYTES); |
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357 | else if (kind == 'P') |
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358 | { |
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359 | /* set the value of a single CPU register - return OK */ |
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360 | unsigned long regno; |
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361 | |
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362 | if (hexToInt (&ptr, ®no) |
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363 | && *ptr++ == '=' |
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364 | && regno < NUMREGS) |
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365 | { |
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366 | hex2mem (ptr, (unsigned long)(unsigned int)(registers.r + regno), |
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367 | regno == PC ? 4 : 2); |
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368 | putPacket ("OK"); |
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369 | } |
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370 | else |
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371 | putPacket ("E01"); |
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372 | } |
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373 | else if (kind == 'G') |
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374 | { |
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375 | /* set the value of the CPU registers - return OK */ |
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376 | hex2mem(ptr, (unsigned long)(unsigned int)®isters, NUMREGBYTES); |
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377 | putPacket ("OK"); |
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378 | } |
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379 | else if (kind == 's' || kind == 'c') |
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380 | { |
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381 | /* sAA..AA Step one instruction from AA..AA(optional) */ |
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382 | /* cAA..AA Continue from address AA..AA(optional) */ |
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383 | /* try to read optional parameter, pc unchanged if no parm */ |
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384 | |
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385 | is_running = 1; |
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386 | |
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387 | if (hexToInt(&ptr,&addr)) |
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388 | registers.pc = addr; |
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389 | |
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390 | if (kind == 's') /* single-stepping */ |
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391 | prepare_to_step(); |
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392 | return; |
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393 | } |
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394 | else if (kind == 'k') |
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395 | { |
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396 | /* kill the program */ |
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397 | assign_regs (®isters, &orig_registers); |
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398 | is_running = 0; |
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399 | putPacket (""); |
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400 | } |
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401 | else |
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402 | /* Unknown code. Return an empty reply message. */ |
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403 | putPacket (""); |
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404 | } |
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405 | } |
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406 | |
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407 | static int |
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408 | hex (int ch) |
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409 | { |
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410 | if ((ch >= '0') && (ch <= '9')) return (ch-'0'); |
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411 | if ((ch >= 'a') && (ch <= 'f')) return (ch-'a'+10); |
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412 | if ((ch >= 'A') && (ch <= 'F')) return (ch-'A'+10); |
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413 | return (-1); |
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414 | } |
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415 | |
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416 | /* scan for the sequence $<data>#<checksum> */ |
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417 | |
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418 | static unsigned char * |
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419 | getpacket (void) |
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420 | { |
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421 | unsigned char *buffer = &remcomBuffer[0]; |
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422 | unsigned checksum; |
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423 | int count; |
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424 | char ch; |
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425 | |
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426 | while (1) |
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427 | { |
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428 | /* wait around for the start character, ignore all other characters */ |
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429 | while (getDebugChar () != '$') |
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430 | ; |
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431 | |
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432 | checksum = 0; |
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433 | count = 0; |
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434 | while ((ch = getDebugChar ()) == '$') |
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435 | ; |
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436 | |
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437 | /* now, read until a # or end of buffer is found */ |
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438 | while (ch != '#' && count < BUFMAX - 1) |
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439 | { |
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440 | checksum = checksum + ch; |
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441 | buffer[count] = ch; |
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442 | count = count + 1; |
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443 | ch = getDebugChar (); |
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444 | } |
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445 | buffer[count] = 0; |
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446 | |
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447 | if (ch == '#') |
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448 | { |
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449 | unsigned xmitcsum; |
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450 | ch = getDebugChar (); |
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451 | xmitcsum = hex (ch) << 4; |
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452 | ch = getDebugChar (); |
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453 | xmitcsum += hex (ch); |
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454 | |
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455 | /* If one of the above 'hex' calls returns -1, xmitcsum will |
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456 | have high bits set, and so the test below will fail. */ |
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457 | |
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458 | if ((checksum & 0xFF) != xmitcsum) |
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459 | putDebugChar ('-'); /* failed checksum */ |
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460 | else |
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461 | { |
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462 | putDebugChar ('+'); /* successful transfer */ |
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463 | return &buffer[0]; |
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464 | } |
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465 | } |
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466 | } |
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467 | } |
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468 | |
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469 | /* send the packet in buffer. */ |
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470 | |
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471 | static void |
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472 | putPacket (unsigned char *buffer_p) |
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473 | { |
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474 | /* $<packet info>#<checksum>. */ |
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475 | do { |
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476 | unsigned checksum; |
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477 | unsigned char *buffer = buffer_p; |
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478 | |
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479 | putDebugChar('$'); |
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480 | checksum = 0; |
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481 | |
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482 | while (*buffer) { |
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483 | putDebugChar(*buffer); |
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484 | checksum += *buffer; |
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485 | buffer++; |
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486 | } |
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487 | putDebugChar('#'); |
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488 | putDebugChar(hexchars[(checksum >> 4) % 16]); |
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489 | putDebugChar(hexchars[checksum % 16]); |
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490 | } while (getDebugChar() != '+'); |
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491 | } |
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492 | |
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493 | /* Convert the memory pointed to by mem into hex, and return it as a packet. */ |
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494 | |
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495 | static void |
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496 | putHex (char c, unsigned long mem_arg, int count) |
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497 | { |
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498 | do { |
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499 | unsigned long mem = mem_arg; |
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500 | int i; |
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501 | unsigned checksum; |
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502 | |
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503 | putDebugChar('$'); |
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504 | checksum = 0; |
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505 | |
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506 | if (c) |
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507 | { |
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508 | checksum = c; |
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509 | putDebugChar(c); |
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510 | } |
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511 | |
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512 | for (i = 0; i < count; i++) |
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513 | { |
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514 | unsigned char c = get_char (mem); |
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515 | char ch = hexchars[c >> 4]; |
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516 | putDebugChar(ch); |
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517 | checksum += ch; |
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518 | ch = hexchars[c % 16]; |
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519 | putDebugChar(ch); |
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520 | checksum += ch; |
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521 | mem++; |
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522 | } |
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523 | putDebugChar('#'); |
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524 | putDebugChar(hexchars[(checksum >> 4) % 16]); |
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525 | putDebugChar(hexchars[checksum % 16]); |
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526 | } while (getDebugChar() != '+'); |
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527 | } |
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528 | |
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529 | /* Function: gdb_write(char *, int) |
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530 | Make gdb write n bytes to stdout (not assumed to be null-terminated). */ |
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531 | |
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532 | void |
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533 | gdb_write (char *data, int len) |
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534 | { |
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535 | ERR_DETECT_REG &= ~SER0_IRQ_ENA; |
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536 | putHex ('O', (unsigned long)(unsigned int)data, len); |
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537 | ERR_DETECT_REG |= SER0_IRQ_ENA; |
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538 | } |
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539 | |
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540 | int |
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541 | gdb_read (char *buf, int nbytes) |
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542 | { |
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543 | int i = 0; |
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544 | |
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545 | ERR_DETECT_REG &= ~SER0_IRQ_ENA; |
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546 | for (i = 0; i < nbytes; i++) |
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547 | { |
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548 | *(buf + i) = getDebugChar(); |
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549 | if ((*(buf + i) == '\n') || (*(buf + i) == '\r')) |
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550 | { |
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551 | (*(buf + i + 1)) = 0; |
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552 | break; |
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553 | } |
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554 | } |
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555 | ERR_DETECT_REG |= SER0_IRQ_ENA; |
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556 | return (i); |
---|
557 | } |
---|
558 | |
---|
559 | static int |
---|
560 | valid_addr_range (unsigned long mem, int count) |
---|
561 | { |
---|
562 | unsigned long last = mem + count - 1; |
---|
563 | |
---|
564 | if (last < 0x800L) |
---|
565 | return 1; |
---|
566 | |
---|
567 | if (mem < 0x7f00L) |
---|
568 | return 0; |
---|
569 | |
---|
570 | if (last > 0x7ffffL) |
---|
571 | return 0; |
---|
572 | |
---|
573 | return 1; |
---|
574 | } |
---|
575 | |
---|
576 | /* Convert the hex array pointed to by buf into binary to be placed in mem. |
---|
577 | Return a pointer to the character AFTER the last byte written. */ |
---|
578 | |
---|
579 | static void |
---|
580 | hex2mem (unsigned char *buf, unsigned long mem, int count) |
---|
581 | { |
---|
582 | int i; |
---|
583 | unsigned char ch; |
---|
584 | |
---|
585 | for (i=0;i<count;i++) |
---|
586 | { |
---|
587 | ch = hex(*buf++) << 4; |
---|
588 | ch = ch + hex(*buf++); |
---|
589 | set_char (mem++, ch); |
---|
590 | } |
---|
591 | } |
---|
592 | |
---|
593 | /**********************************************/ |
---|
594 | /* WHILE WE FIND NICE HEX CHARS, BUILD AN INT */ |
---|
595 | /* RETURN NUMBER OF CHARS PROCESSED */ |
---|
596 | /**********************************************/ |
---|
597 | static int |
---|
598 | hexToInt (unsigned char **ptr, long *intValue) |
---|
599 | { |
---|
600 | int numChars = 0; |
---|
601 | int hexValue; |
---|
602 | |
---|
603 | *intValue = 0; |
---|
604 | while (**ptr) |
---|
605 | { |
---|
606 | hexValue = hex(**ptr); |
---|
607 | if (hexValue >=0) |
---|
608 | { |
---|
609 | *intValue = (*intValue <<4) | (unsigned) hexValue; |
---|
610 | numChars ++; |
---|
611 | } |
---|
612 | else |
---|
613 | break; |
---|
614 | (*ptr)++; |
---|
615 | } |
---|
616 | return (numChars); |
---|
617 | } |
---|
618 | |
---|
619 | |
---|
620 | /* Function: opcode_size |
---|
621 | Determine number of bytes in full opcode by examining first word. |
---|
622 | */ |
---|
623 | static int |
---|
624 | opcode_size(unsigned int opcode) |
---|
625 | { |
---|
626 | if ((opcode & 0xff00) == 0) |
---|
627 | return 2; |
---|
628 | |
---|
629 | if ((opcode & 0xf800) == 0) |
---|
630 | return 4; |
---|
631 | |
---|
632 | if ((opcode & 0xf800) == 0x7800) |
---|
633 | return 4; |
---|
634 | |
---|
635 | if ((opcode & 0xf000) == 0xc000) |
---|
636 | return 4; |
---|
637 | |
---|
638 | if ((opcode & 0xf100) == 0x2000) |
---|
639 | return 4; |
---|
640 | |
---|
641 | if ((opcode & 0xfff0) == 0x30e0) |
---|
642 | return 4; |
---|
643 | |
---|
644 | if ((opcode & 0xf008) == 0x6008) |
---|
645 | return 4; |
---|
646 | |
---|
647 | if ((opcode & 0xf808) == 0x7008) |
---|
648 | return 4; |
---|
649 | |
---|
650 | opcode >>= 8; |
---|
651 | if (opcode == 0x0c || opcode == 0x0d || opcode == 0x31) |
---|
652 | return 4; |
---|
653 | |
---|
654 | return 2; |
---|
655 | } |
---|
656 | |
---|
657 | static struct { |
---|
658 | unsigned long addr; |
---|
659 | unsigned long addr2; |
---|
660 | unsigned int opcode; |
---|
661 | unsigned int opcode2; |
---|
662 | } stepinfo; |
---|
663 | |
---|
664 | /* Function: prepare_to_step |
---|
665 | Called from handle_exception to prepare the user program to single-step. |
---|
666 | Places a trap instruction after the target instruction, with special |
---|
667 | extra handling for branch instructions. |
---|
668 | */ |
---|
669 | |
---|
670 | static void |
---|
671 | prepare_to_step(void) |
---|
672 | { |
---|
673 | unsigned long pc = registers.pc; |
---|
674 | unsigned long next_pc, next_pc2; |
---|
675 | unsigned int op, op2, sp; |
---|
676 | unsigned char op_msb, op_lsb; |
---|
677 | int r12; |
---|
678 | char r8; |
---|
679 | |
---|
680 | op = get_word(pc); |
---|
681 | op_msb = (op >> 8) & 0xff; |
---|
682 | op_lsb = op & 0xff; |
---|
683 | op2 = get_word(pc + 2); |
---|
684 | next_pc = pc + opcode_size(op); |
---|
685 | next_pc2 = 0; |
---|
686 | |
---|
687 | if (op_msb == 0) |
---|
688 | { |
---|
689 | if (op_lsb == 2) |
---|
690 | { |
---|
691 | /* IRET */ |
---|
692 | sp = registers.r[SP]; |
---|
693 | next_pc = *(unsigned *)(sp - 4); |
---|
694 | next_pc = (next_pc << 16) | *(unsigned *)(sp - 6); |
---|
695 | } |
---|
696 | else if (op_lsb == 3) |
---|
697 | { |
---|
698 | /* RET */ |
---|
699 | sp = registers.r[SP]; |
---|
700 | next_pc = *(unsigned *)(sp - 2); |
---|
701 | next_pc = (next_pc << 16) | *(unsigned *)(sp - 4); |
---|
702 | } |
---|
703 | else |
---|
704 | { |
---|
705 | op2 = op_lsb & 0xf0; |
---|
706 | if (op2 && op2 < 0x40) |
---|
707 | { |
---|
708 | /* {CALLR,BR,ICALLR} Rs */ |
---|
709 | next_pc = (pc + 2) + (int)registers.r[op_lsb & 0xf]; |
---|
710 | } |
---|
711 | else if (op2 < 0x80 || op2 == 0xa0 || op2 == 0xb0) |
---|
712 | { |
---|
713 | /* {JMP,ICALL,CALL} Rb,Rs */ |
---|
714 | next_pc = registers.r[(op_lsb & 0x10) ? 9 : 8]; |
---|
715 | next_pc = (next_pc << 16) | (unsigned int)registers.r[op_lsb & 0xf]; |
---|
716 | } |
---|
717 | } |
---|
718 | } |
---|
719 | else if (op_msb < 4) |
---|
720 | { |
---|
721 | /* {CALLF,JMPF,ICALLF} a24 */ |
---|
722 | next_pc = ((unsigned long)op2) << 8; |
---|
723 | next_pc |= op_lsb; |
---|
724 | } |
---|
725 | else if (op_msb < 8) |
---|
726 | { |
---|
727 | if ((op2 & 0xf000) == 0) |
---|
728 | { |
---|
729 | /* Bx Rd,#imm4,r12 */ |
---|
730 | /* Bx Rd,Rs,r12 */ |
---|
731 | r12 = op2 << 4; |
---|
732 | r12 >>= 4; |
---|
733 | next_pc2 = (pc + 4) + r12; |
---|
734 | } |
---|
735 | } |
---|
736 | else if (op_msb == 0x0c || op_msb == 0x0d || (op_msb & 0xf1) == 0x20 || |
---|
737 | ((op_msb >= 0x7c && op_msb <= 0x7f) && (op2 & 0x8000) == 0)) |
---|
738 | { |
---|
739 | /* Bxx Rd,Rs,r12 */ |
---|
740 | /* Bxx Rd,#imm8,r12 */ |
---|
741 | /* Bx m8,#imm3,r12 */ |
---|
742 | /* Bx s8,#imm3,r12 */ |
---|
743 | r12 = op2 << 4; |
---|
744 | r12 >>= 4; |
---|
745 | next_pc2 = (pc + 4) + r12; |
---|
746 | } |
---|
747 | else if ((op_msb & 0xf0) == 0x10) |
---|
748 | { |
---|
749 | /* {BR,CALLR} r12 */ |
---|
750 | r12 = (op & 0xffe) << 4; |
---|
751 | r12 >>= 4; |
---|
752 | next_pc = (pc + 2) + r12; |
---|
753 | } |
---|
754 | else if ((op_msb & 0xe0) == 0xc0) |
---|
755 | { |
---|
756 | /* Bxx Rx,#imm16,r8 */ |
---|
757 | /* TBxx r8 */ |
---|
758 | r8 = op_lsb; |
---|
759 | next_pc2 = next_pc + r8; |
---|
760 | } |
---|
761 | |
---|
762 | stepinfo.addr = next_pc; |
---|
763 | stepinfo.opcode = get_word(next_pc); |
---|
764 | set_word(next_pc, BREAKPOINT_OPCODE); |
---|
765 | |
---|
766 | if (next_pc2) |
---|
767 | { |
---|
768 | stepinfo.addr2 = next_pc2; |
---|
769 | stepinfo.opcode2 = get_word(next_pc2); |
---|
770 | set_word(next_pc2, BREAKPOINT_OPCODE); |
---|
771 | } |
---|
772 | } |
---|
773 | |
---|
774 | /* Function: finish_from_step |
---|
775 | Called from handle_exception to finish up when the user program |
---|
776 | returns from a single-step. Replaces the instructions that had |
---|
777 | been overwritten by breakpoint. */ |
---|
778 | |
---|
779 | static void |
---|
780 | finish_from_step (void) |
---|
781 | { |
---|
782 | if (stepinfo.addr) /* anything to do? */ |
---|
783 | { |
---|
784 | set_word(stepinfo.addr, stepinfo.opcode); |
---|
785 | stepinfo.addr = 0; |
---|
786 | if (stepinfo.addr2) |
---|
787 | { |
---|
788 | set_word(stepinfo.addr2, stepinfo.opcode2); |
---|
789 | stepinfo.addr2 = 0; |
---|
790 | } |
---|
791 | } |
---|
792 | } |
---|
793 | |
---|
794 | |
---|
795 | /* |
---|
796 | * UART support |
---|
797 | */ |
---|
798 | #define UART0_BASE 0x7f38 |
---|
799 | #define UART1_BASE 0x7f48 |
---|
800 | |
---|
801 | #define UART_CR(base) (*(volatile unsigned char *)(base)) |
---|
802 | #define UART_RXD(base) (*(volatile unsigned int *)((base) + 2)) |
---|
803 | #define UART_TXD(base) (*(volatile unsigned int *)((base) + 4)) |
---|
804 | |
---|
805 | #define UART_CR_RUN 0x80 |
---|
806 | #define UART_CR_ERR 0x40 |
---|
807 | #define UART_CR_BAUD_115k 0x20 |
---|
808 | #define UART_CR_PARITY 0x10 |
---|
809 | #define UART_CR_TXEMPTY 0x08 |
---|
810 | #define UART_CR_TXIEN 0x04 |
---|
811 | #define UART_CR_RXRDY 0x02 |
---|
812 | #define UART_CR_RXIEN 0x01 |
---|
813 | |
---|
814 | #define DBG_UART UART0_BASE |
---|
815 | |
---|
816 | static void |
---|
817 | putDebugChar(unsigned ch) |
---|
818 | { |
---|
819 | while ((UART_CR(DBG_UART) & UART_CR_TXEMPTY) == 0) ; |
---|
820 | |
---|
821 | UART_TXD(DBG_UART) = ch; |
---|
822 | } |
---|
823 | |
---|
824 | static unsigned char |
---|
825 | getDebugChar(void) |
---|
826 | { |
---|
827 | while ((UART_CR(DBG_UART) & UART_CR_RXRDY) == 0) ; |
---|
828 | |
---|
829 | return UART_RXD(DBG_UART); |
---|
830 | } |
---|
831 | |
---|
832 | void |
---|
833 | uart_init(void) |
---|
834 | { |
---|
835 | UART_CR(DBG_UART) |= (UART_CR_RUN | UART_CR_RXIEN); |
---|
836 | } |
---|
837 | |
---|