Last change
on this file was
444,
checked in by satin@…, 6 years ago
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add newlib,libalmos-mkh, restructure shared_syscalls.h and mini-libc
|
File size:
875 bytes
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Line | |
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1 | .file "memchr.S" |
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2 | |
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3 | .section .text |
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4 | |
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5 | .global _memchr |
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6 | .type _memchr,@function |
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7 | _memchr: |
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8 | ;; R1: string pointer |
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9 | ;; R2: byte sought |
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10 | ;; R3: max number to scan |
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11 | #ifdef __RX_DISALLOW_STRING_INSNS__ |
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12 | mov.b r2, r2 ; The mov.b below sign extends as it loads, so make sure that r2 is sign-extended as well. |
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13 | 2: cmp #0, r3 |
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14 | beq 1f |
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15 | sub #1, r3 |
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16 | mov.b [r1+], r5 |
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17 | cmp r5, r2 |
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18 | bne 2b |
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19 | |
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20 | sub #1, r1 ; We have found a match, bit now R1 points to the byte after the match. |
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21 | 1: rts |
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22 | #else |
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23 | cmp #0, r3 ; If r3 is 0 suntil.b will do nothing and not set any flags... |
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24 | stz #1, r1 ; ...so store 1 into r1. It will be decremented by the SUB later. |
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25 | suntil.b ; Search until *r1 == r2 or r3 bytes have been examined. |
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26 | stnz #1, r1 ; If no match was found return NULL. |
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27 | sub #1, r1 ; suntil.b leaves r1 pointing at the address *after* the match. |
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28 | rts |
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29 | #endif |
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30 | |
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31 | .size _memchr, . - _memchr |
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32 | |
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