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