source: soft/tp16/correction/reset.s @ 88

Last change on this file since 88 was 43, checked in by alain, 13 years ago

Two modifs in isr.s and drivers.c to support one multi_timer
per processor in clusterized multi-processors architectures.
(same segment increment as the multi_tty)
File size: 2.2 KB
Line 
1#################################################################################
2#       File : reset.s
3#       Author : Alain Greiner
4#       Date : 15/09/2010
5#################################################################################
6#       This is an improved boot code supporting IOC and DMA peripherals :
7#       - It initializes the Status Register (SR)
8#       - It defines the stack sizes  and initializes the stack pointers ($29)
9#       - It initializes the interrupt vector with 4 ISR addresses
10#         (tty, timer,dma,block-device), and initialises the ICU.
11#       - It initializes the EPC register, and jumps to the main in user mode.
12#################################################################################
13               
14        .section .reset,"ax",@progbits
15
16        .extern seg_stack_base
17        .extern seg_icu_base
18        .extern _interrupt_vector
19        .extern _isr_tty_get_task0
20        .extern _isr_timer
21        .extern _isr_dma
22        .extern _isr_ioc
23        .extern main
24
25        .globl  reset                           # makes reset an external symbol
26        .ent    reset
27        .align  2
28
29reset:
30    .set noreorder
31
32# initializes stack pointers
33        la      $29,    seg_stack_base         
34        li      $26,    0x40000
35        addu    $29,    $29,    $26             # stack size = 256 Kbytes
36
37# initializes interrupt vector
38    la      $26,    _interrupt_vector       # interrupt vector address
39    la      $27,    _isr_timer              # isr_timer address
40    sw      $27,    0($26)                  # interrupt_vector[0] <= _isr_timer
41    la      $27,    _isr_tty_get_task0      # isr_tty_get_task0 address
42    sw      $27,    4($26)                  # interrupt_vector[1] <= _isr_tty_get_task0
43    la      $27,    _isr_ioc                # isr_ioc address
44    sw      $27,   20($26)                  # interrupt_vector[5] <= _isr_ioc
45    la      $27,    _isr_dma                # isr_dma address
46    sw      $27,   24($26)                  # interrupt_vector[6] <= _isr_dma
47
48# initializes ICU
49    la      $26,    seg_icu_base
50    li      $27,    0x63                    # IRQ[0] IRQ[1] IRQ[5] IRQ[6]
51    sw      $27,    8($26)                  # ICU_MASK_SET
52
53# initializes SR register
54    li      $26,        0x0000FF13              # Interrupt enabled
55    mtc0        $26,    $12             # SR <= 0xFF13
56
57# jump to main in user mode
58        la      $26,    main
59        mtc0    $26,    $14
60        eret
61
62        .align 2
63
64        .end    reset
65        .size   reset, .-reset
66
67        .set reorder
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