| Heiko Carstens | 535c611 | 2012-08-14 13:20:20 +0200 | [diff] [blame] | 1 | /* |
| 2 | * String handling functions. |
| 3 | * |
| 4 | * Copyright IBM Corp. 2012 |
| 5 | */ |
| 6 | |
| 7 | #include <linux/linkage.h> |
| 8 | |
| 9 | /* |
| 10 | * memset implementation |
| 11 | * |
| 12 | * This code corresponds to the C construct below. We do distinguish |
| 13 | * between clearing (c == 0) and setting a memory array (c != 0) simply |
| 14 | * because nearly all memset invocations in the kernel clear memory and |
| 15 | * the xc instruction is preferred in such cases. |
| 16 | * |
| 17 | * void *memset(void *s, int c, size_t n) |
| 18 | * { |
| 19 | * if (likely(c == 0)) |
| 20 | * return __builtin_memset(s, 0, n); |
| 21 | * return __builtin_memset(s, c, n); |
| 22 | * } |
| 23 | */ |
| 24 | ENTRY(memset) |
| 25 | basr %r5,%r0 |
| 26 | .Lmemset_base: |
| 27 | ltr %r4,%r4 |
| 28 | bzr %r14 |
| 29 | ltr %r3,%r3 |
| 30 | jnz .Lmemset_fill |
| 31 | ahi %r4,-1 |
| 32 | lr %r3,%r4 |
| 33 | srl %r3,8 |
| 34 | ltr %r3,%r3 |
| 35 | lr %r1,%r2 |
| 36 | je .Lmemset_clear_rest |
| 37 | .Lmemset_clear_loop: |
| 38 | xc 0(256,%r1),0(%r1) |
| 39 | la %r1,256(%r1) |
| 40 | brct %r3,.Lmemset_clear_loop |
| 41 | .Lmemset_clear_rest: |
| 42 | ex %r4,.Lmemset_xc-.Lmemset_base(%r5) |
| 43 | br %r14 |
| 44 | .Lmemset_fill: |
| 45 | stc %r3,0(%r2) |
| 46 | chi %r4,1 |
| 47 | lr %r1,%r2 |
| 48 | ber %r14 |
| 49 | ahi %r4,-2 |
| 50 | lr %r3,%r4 |
| 51 | srl %r3,8 |
| 52 | ltr %r3,%r3 |
| 53 | je .Lmemset_fill_rest |
| 54 | .Lmemset_fill_loop: |
| 55 | mvc 1(256,%r1),0(%r1) |
| 56 | la %r1,256(%r1) |
| 57 | brct %r3,.Lmemset_fill_loop |
| 58 | .Lmemset_fill_rest: |
| 59 | ex %r4,.Lmemset_mvc-.Lmemset_base(%r5) |
| 60 | br %r14 |
| 61 | .Lmemset_xc: |
| 62 | xc 0(1,%r1),0(%r1) |
| 63 | .Lmemset_mvc: |
| 64 | mvc 1(1,%r1),0(%r1) |
| 65 | |
| 66 | /* |
| 67 | * memcpy implementation |
| 68 | * |
| 69 | * void *memcpy(void *dest, const void *src, size_t n) |
| 70 | */ |
| 71 | ENTRY(memcpy) |
| 72 | basr %r5,%r0 |
| 73 | .Lmemcpy_base: |
| 74 | ltr %r4,%r4 |
| 75 | bzr %r14 |
| 76 | ahi %r4,-1 |
| 77 | lr %r0,%r4 |
| 78 | srl %r0,8 |
| 79 | ltr %r0,%r0 |
| 80 | lr %r1,%r2 |
| 81 | jnz .Lmemcpy_loop |
| 82 | .Lmemcpy_rest: |
| 83 | ex %r4,.Lmemcpy_mvc-.Lmemcpy_base(%r5) |
| 84 | br %r14 |
| 85 | .Lmemcpy_loop: |
| 86 | mvc 0(256,%r1),0(%r3) |
| 87 | la %r1,256(%r1) |
| 88 | la %r3,256(%r3) |
| 89 | brct %r0,.Lmemcpy_loop |
| 90 | j .Lmemcpy_rest |
| 91 | .Lmemcpy_mvc: |
| 92 | mvc 0(1,%r1),0(%r3) |