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Diffstat (limited to 'arch/arm26/lib/memzero.S')
| -rw-r--r-- | arch/arm26/lib/memzero.S | 80 |
1 files changed, 80 insertions, 0 deletions
diff --git a/arch/arm26/lib/memzero.S b/arch/arm26/lib/memzero.S new file mode 100644 index 000000000000..cc5bf6860061 --- /dev/null +++ b/arch/arm26/lib/memzero.S | |||
| @@ -0,0 +1,80 @@ | |||
| 1 | /* | ||
| 2 | * linux/arch/arm26/lib/memzero.S | ||
| 3 | * | ||
| 4 | * Copyright (C) 1995-2000 Russell King | ||
| 5 | * | ||
| 6 | * This program is free software; you can redistribute it and/or modify | ||
| 7 | * it under the terms of the GNU General Public License version 2 as | ||
| 8 | * published by the Free Software Foundation. | ||
| 9 | */ | ||
| 10 | #include <linux/linkage.h> | ||
| 11 | #include <asm/assembler.h> | ||
| 12 | |||
| 13 | .text | ||
| 14 | .align 5 | ||
| 15 | .word 0 | ||
| 16 | /* | ||
| 17 | * Align the pointer in r0. r3 contains the number of bytes that we are | ||
| 18 | * mis-aligned by, and r1 is the number of bytes. If r1 < 4, then we | ||
| 19 | * don't bother; we use byte stores instead. | ||
| 20 | */ | ||
| 21 | 1: subs r1, r1, #4 @ 1 do we have enough | ||
| 22 | blt 5f @ 1 bytes to align with? | ||
| 23 | cmp r3, #2 @ 1 | ||
| 24 | strltb r2, [r0], #1 @ 1 | ||
| 25 | strleb r2, [r0], #1 @ 1 | ||
| 26 | strb r2, [r0], #1 @ 1 | ||
| 27 | add r1, r1, r3 @ 1 (r1 = r1 - (4 - r3)) | ||
| 28 | /* | ||
| 29 | * The pointer is now aligned and the length is adjusted. Try doing the | ||
| 30 | * memzero again. | ||
| 31 | */ | ||
| 32 | |||
| 33 | ENTRY(__memzero) | ||
| 34 | mov r2, #0 @ 1 | ||
| 35 | ands r3, r0, #3 @ 1 unaligned? | ||
| 36 | bne 1b @ 1 | ||
| 37 | /* | ||
| 38 | * r3 = 0, and we know that the pointer in r0 is aligned to a word boundary. | ||
| 39 | */ | ||
| 40 | cmp r1, #16 @ 1 we can skip this chunk if we | ||
| 41 | blt 4f @ 1 have < 16 bytes | ||
| 42 | /* | ||
| 43 | * We need an extra register for this loop - save the return address and | ||
| 44 | * use the LR | ||
| 45 | */ | ||
| 46 | str lr, [sp, #-4]! @ 1 | ||
| 47 | mov ip, r2 @ 1 | ||
| 48 | mov lr, r2 @ 1 | ||
| 49 | |||
| 50 | 3: subs r1, r1, #64 @ 1 write 32 bytes out per loop | ||
| 51 | stmgeia r0!, {r2, r3, ip, lr} @ 4 | ||
| 52 | stmgeia r0!, {r2, r3, ip, lr} @ 4 | ||
| 53 | stmgeia r0!, {r2, r3, ip, lr} @ 4 | ||
| 54 | stmgeia r0!, {r2, r3, ip, lr} @ 4 | ||
| 55 | bgt 3b @ 1 | ||
| 56 | LOADREGS(eqfd, sp!, {pc}) @ 1/2 quick exit | ||
| 57 | /* | ||
| 58 | * No need to correct the count; we're only testing bits from now on | ||
| 59 | */ | ||
| 60 | tst r1, #32 @ 1 | ||
| 61 | stmneia r0!, {r2, r3, ip, lr} @ 4 | ||
| 62 | stmneia r0!, {r2, r3, ip, lr} @ 4 | ||
| 63 | tst r1, #16 @ 1 16 bytes or more? | ||
| 64 | stmneia r0!, {r2, r3, ip, lr} @ 4 | ||
| 65 | ldr lr, [sp], #4 @ 1 | ||
| 66 | |||
| 67 | 4: tst r1, #8 @ 1 8 bytes or more? | ||
| 68 | stmneia r0!, {r2, r3} @ 2 | ||
| 69 | tst r1, #4 @ 1 4 bytes or more? | ||
| 70 | strne r2, [r0], #4 @ 1 | ||
| 71 | /* | ||
| 72 | * When we get here, we've got less than 4 bytes to zero. We | ||
| 73 | * may have an unaligned pointer as well. | ||
| 74 | */ | ||
| 75 | 5: tst r1, #2 @ 1 2 bytes or more? | ||
| 76 | strneb r2, [r0], #1 @ 1 | ||
| 77 | strneb r2, [r0], #1 @ 1 | ||
| 78 | tst r1, #1 @ 1 a byte left over | ||
| 79 | strneb r2, [r0], #1 @ 1 | ||
| 80 | RETINSTR(mov,pc,lr) @ 1 | ||