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Last change
on this file since 444 was
444,
checked in by satin@…, 6 years ago
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add newlib,libalmos-mkh, restructure shared_syscalls.h and mini-libc
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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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