1/* 2 * String handling functions. 3 * 4 * Copyright IBM Corp. 2012 5 */ 6 7#include <linux/linkage.h> 8#include <asm/export.h> 9 10/* 11 * memset implementation 12 * 13 * This code corresponds to the C construct below. We do distinguish 14 * between clearing (c == 0) and setting a memory array (c != 0) simply 15 * because nearly all memset invocations in the kernel clear memory and 16 * the xc instruction is preferred in such cases. 17 * 18 * void *memset(void *s, int c, size_t n) 19 * { 20 * if (likely(c == 0)) 21 * return __builtin_memset(s, 0, n); 22 * return __builtin_memset(s, c, n); 23 * } 24 */ 25ENTRY(memset) 26 ltgr %r4,%r4 27 bzr %r14 28 ltgr %r3,%r3 29 jnz .Lmemset_fill 30 aghi %r4,-1 31 srlg %r3,%r4,8 32 ltgr %r3,%r3 33 lgr %r1,%r2 34 jz .Lmemset_clear_rest 35.Lmemset_clear_loop: 36 xc 0(256,%r1),0(%r1) 37 la %r1,256(%r1) 38 brctg %r3,.Lmemset_clear_loop 39.Lmemset_clear_rest: 40 larl %r3,.Lmemset_xc 41 ex %r4,0(%r3) 42 br %r14 43.Lmemset_fill: 44 stc %r3,0(%r2) 45 cghi %r4,1 46 lgr %r1,%r2 47 ber %r14 48 aghi %r4,-2 49 srlg %r3,%r4,8 50 ltgr %r3,%r3 51 jz .Lmemset_fill_rest 52.Lmemset_fill_loop: 53 mvc 1(256,%r1),0(%r1) 54 la %r1,256(%r1) 55 brctg %r3,.Lmemset_fill_loop 56.Lmemset_fill_rest: 57 larl %r3,.Lmemset_mvc 58 ex %r4,0(%r3) 59 br %r14 60.Lmemset_xc: 61 xc 0(1,%r1),0(%r1) 62.Lmemset_mvc: 63 mvc 1(1,%r1),0(%r1) 64EXPORT_SYMBOL(memset) 65 66/* 67 * memcpy implementation 68 * 69 * void *memcpy(void *dest, const void *src, size_t n) 70 */ 71ENTRY(memcpy) 72 ltgr %r4,%r4 73 bzr %r14 74 aghi %r4,-1 75 srlg %r5,%r4,8 76 ltgr %r5,%r5 77 lgr %r1,%r2 78 jnz .Lmemcpy_loop 79.Lmemcpy_rest: 80 larl %r5,.Lmemcpy_mvc 81 ex %r4,0(%r5) 82 br %r14 83.Lmemcpy_loop: 84 mvc 0(256,%r1),0(%r3) 85 la %r1,256(%r1) 86 la %r3,256(%r3) 87 brctg %r5,.Lmemcpy_loop 88 j .Lmemcpy_rest 89.Lmemcpy_mvc: 90 mvc 0(1,%r1),0(%r3) 91EXPORT_SYMBOL(memcpy) 92