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#include "ultra64/asm.h"
#include "ultra64/regdef.h"
.text
LEAF(bzero)
negu v1, a0
blt a1, 0xC, bytezero
and v1, v1, 3
subu a1, a1, v1
beqz v1, blkzero
swl zero, (a0)
addu a0, a0, v1
blkzero:
/* align backwards to 0x20 */
and a3, a1, ~(0x20 - 1)
/* If the result is zero, the amount to zero is less than 0x20 bytes */
subu a1, a1, a3
beqz a3, wordzero
/* zero in blocks of 0x20 at a time */
addu a3, a3, a0
1:
sw zero, 0(a0)
sw zero, 4(a0)
sw zero, 8(a0)
sw zero, 12(a0)
addiu a0, a0, 0x20
sw zero, -16(a0)
sw zero, -12(a0)
sw zero, -8(a0)
sw zero, -4(a0)
bne a0, a3, 1b
wordzero:
/* align backwards to 0x4 */
and a3, a1, ~3
/* If the result is zero, the amount to zero is less than 0x4 bytes */
subu a1, a1, a3
beqz a3, bytezero
/* zero one word at a time */
addu a3, a3, a0
1:
addu a0, a0, 4
sw zero, -4(a0)
bne a0, a3, 1b
bytezero:
/* test if nothing left to zero */
blez a1, zerodone
/* zero one byte at a time */
addu a1, a1, a0
1:
addiu a0, a0, 1
sb zero, -1(a0)
bne a0, a1, 1b
zerodone:
jr ra
END(bzero)
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