diff options
Diffstat (limited to 'sysdeps/alpha/submul_1.s')
| -rw-r--r-- | sysdeps/alpha/submul_1.s | 23 |
1 files changed, 7 insertions, 16 deletions
diff --git a/sysdeps/alpha/submul_1.s b/sysdeps/alpha/submul_1.s index acaa11c545..292b2c18b6 100644 --- a/sysdeps/alpha/submul_1.s +++ b/sysdeps/alpha/submul_1.s @@ -26,16 +26,7 @@ # size r18 # s2_limb r19 - # This code runs at 42 cycles/limb on the 21064. - - # To improve performance for long multiplications, we would use - # 'fetch' for S1 and 'fetch_m' for RES. It's not obvious how to use - # these instructions without slowing down the general code: 1. We can - # only have two prefetches in operation at any time in the Alpha - # architecture. 2. There will seldom be any special alignment - # between RES_PTR and S1_PTR. Maybe we can simply divide the current - # loop into an inner and outer loop, having the inner loop handle - # exactly one prefetch block? + # This code runs at 42 cycles/limb on EV4 and 18 cycles/limb on EV5. .set noreorder .set noat @@ -52,7 +43,7 @@ __mpn_submul_1: mulq $2,$19,$3 # $3 = prod_low ldq $5,0($16) # $5 = *res_ptr umulh $2,$19,$0 # $0 = prod_high - beq $18,Lend1 # jump if size was == 1 + beq $18,.Lend1 # jump if size was == 1 ldq $2,0($17) # $2 = s1_limb addq $17,8,$17 # s1_ptr++ subq $18,1,$18 # size-- @@ -60,10 +51,10 @@ __mpn_submul_1: cmpult $5,$3,$4 stq $3,0($16) addq $16,8,$16 # res_ptr++ - beq $18,Lend2 # jump if size was == 2 + beq $18,.Lend2 # jump if size was == 2 .align 3 -Loop: mulq $2,$19,$3 # $3 = prod_low +.Loop: mulq $2,$19,$3 # $3 = prod_low ldq $5,0($16) # $5 = *res_ptr addq $4,$0,$0 # cy_limb = cy_limb + 'cy' subq $18,1,$18 # size-- @@ -77,9 +68,9 @@ Loop: mulq $2,$19,$3 # $3 = prod_low stq $3,0($16) addq $16,8,$16 # res_ptr++ addq $5,$0,$0 # combine carries - bne $18,Loop + bne $18,.Loop -Lend2: mulq $2,$19,$3 # $3 = prod_low +.Lend2: mulq $2,$19,$3 # $3 = prod_low ldq $5,0($16) # $5 = *res_ptr addq $4,$0,$0 # cy_limb = cy_limb + 'cy' umulh $2,$19,$4 # $4 = cy_limb @@ -91,7 +82,7 @@ Lend2: mulq $2,$19,$3 # $3 = prod_low addq $5,$0,$0 # combine carries addq $4,$0,$0 # cy_limb = prod_high + cy ret $31,($26),1 -Lend1: subq $5,$3,$3 +.Lend1: subq $5,$3,$3 cmpult $5,$3,$5 stq $3,0($16) addq $0,$5,$0 |