memset.S
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/*
* linux/arch/alpha/lib/memset.S
*
* This is an efficient (and small) implementation of the C library "memset()"
* function for the alpha.
*
* (C) Copyright 1996 Linus Torvalds
*
* This routine is "moral-ware": you are free to use it any way you wish, and
* the only obligation I put on you is a moral one: if you make any improvements
* to the routine, please send me your improvements for me to use similarly.
*
* The scheduling comments are according to the EV5 documentation (and done by
* hand, so they might well be incorrect, please do tell me about it..)
*/
.set noat
.set noreorder
.text
.globl memset
.globl __memset
.globl ___memset
.globl __memsetw
.globl __constant_c_memset
.ent ___memset
.align 5
___memset:
.frame $30,0,$26,0
.prologue 0
and $17,255,$1 /* E1 */
insbl $17,1,$17 /* .. E0 */
bis $17,$1,$17 /* E0 (p-c latency, next cycle) */
sll $17,16,$1 /* E1 (p-c latency, next cycle) */
bis $17,$1,$17 /* E0 (p-c latency, next cycle) */
sll $17,32,$1 /* E1 (p-c latency, next cycle) */
bis $17,$1,$17 /* E0 (p-c latency, next cycle) */
ldq_u $31,0($30) /* .. E1 */
.align 5
__constant_c_memset:
addq $18,$16,$6 /* E0 */
bis $16,$16,$0 /* .. E1 */
xor $16,$6,$1 /* E0 */
ble $18,end /* .. E1 */
bic $1,7,$1 /* E0 */
beq $1,within_one_quad /* .. E1 (note EV5 zero-latency forwarding) */
and $16,7,$3 /* E0 */
beq $3,aligned /* .. E1 (note EV5 zero-latency forwarding) */
ldq_u $4,0($16) /* E0 */
bis $16,$16,$5 /* .. E1 */
insql $17,$16,$2 /* E0 */
subq $3,8,$3 /* .. E1 */
addq $18,$3,$18 /* E0 $18 is new count ($3 is negative) */
mskql $4,$16,$4 /* .. E1 (and possible load stall) */
subq $16,$3,$16 /* E0 $16 is new aligned destination */
bis $2,$4,$1 /* .. E1 */
bis $31,$31,$31 /* E0 */
ldq_u $31,0($30) /* .. E1 */
stq_u $1,0($5) /* E0 */
bis $31,$31,$31 /* .. E1 */
.align 4
aligned:
sra $18,3,$3 /* E0 */
and $18,7,$18 /* .. E1 */
bis $16,$16,$5 /* E0 */
beq $3,no_quad /* .. E1 */
.align 3
loop:
stq $17,0($5) /* E0 */
subq $3,1,$3 /* .. E1 */
addq $5,8,$5 /* E0 */
bne $3,loop /* .. E1 */
no_quad:
bis $31,$31,$31 /* E0 */
beq $18,end /* .. E1 */
ldq $7,0($5) /* E0 */
mskqh $7,$6,$2 /* .. E1 (and load stall) */
insqh $17,$6,$4 /* E0 */
bis $2,$4,$1 /* .. E1 */
stq $1,0($5) /* E0 */
ret $31,($26),1 /* .. E1 */
.align 3
within_one_quad:
ldq_u $1,0($16) /* E0 */
insql $17,$16,$2 /* E1 */
mskql $1,$16,$4 /* E0 (after load stall) */
bis $2,$4,$2 /* E0 */
mskql $2,$6,$4 /* E0 */
mskqh $1,$6,$2 /* .. E1 */
bis $2,$4,$1 /* E0 */
stq_u $1,0($16) /* E0 */
end:
ret $31,($26),1 /* E1 */
.end ___memset
.align 5
.ent __memsetw
__memsetw:
.prologue 0
inswl $17,0,$1 /* E0 */
inswl $17,2,$2 /* E0 */
inswl $17,4,$3 /* E0 */
or $1,$2,$1 /* .. E1 */
inswl $17,6,$4 /* E0 */
or $1,$3,$1 /* .. E1 */
or $1,$4,$17 /* E0 */
br __constant_c_memset /* .. E1 */
.end __memsetw
memset = ___memset
__memset = ___memset