| /* |
| * memcmp.c |
| */ |
| |
| #include <string.h> |
| |
| int memcmp(const void *s1, const void *s2, size_t n) |
| { |
| int d = 0; |
| |
| #if defined(ARCH_cortex_m3) || defined(ARCH_cortex_m4) || defined(ARCH_cortex_m7) |
| asm (".syntax unified \n" |
| " push {r4, r5, r6} \n" |
| " mov r5, #0 \n" |
| " and r6, r2, #0xfffffffc \n" |
| " b test1 \n" |
| "loop1: ldr r3, [r0, r5] \n" |
| " ldr r4, [r1, r5] \n" |
| " cmp r3, r4 \n" |
| " bne res1 \n" |
| " add r5, #4 \n" |
| "test1: cmp r5, r6 \n" |
| " bne loop1 \n" |
| " b test2 \n" |
| "res1: rev r3, r3 \n" |
| " rev r4, r4 \n" |
| " subs r3, r4 \n" |
| " ite hi \n" |
| " movhi r3, #1 \n" |
| " movls r3, #-1 \n" |
| " b done \n" |
| "loop2: ldrb r3, [r0, r5] \n" |
| " ldrb r4, [r1, r5] \n" |
| " subs r3, r4 \n" |
| " bne done \n" |
| " add r5, #1 \n" |
| "test2: cmp r5, r2 \n" |
| " bne loop2 \n" |
| " mov r3, #0 \n" |
| "done: mov %[res], r3 \n" |
| " pop {r4, r5, r6} \n" |
| : [res] "=r" (d) |
| ); |
| #else |
| const unsigned char *c1 = s1, *c2 = s2; |
| |
| while (n--) { |
| d = (int)*c1++ - (int)*c2++; |
| if (d) |
| break; |
| } |
| #endif |
| |
| return d; |
| } |
