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Diffstat (limited to 'gmp/mpn/a29k/sub_n.s')
| -rw-r--r-- | gmp/mpn/a29k/sub_n.s | 118 |
1 files changed, 118 insertions, 0 deletions
diff --git a/gmp/mpn/a29k/sub_n.s b/gmp/mpn/a29k/sub_n.s new file mode 100644 index 0000000000..42072a494d --- /dev/null +++ b/gmp/mpn/a29k/sub_n.s @@ -0,0 +1,118 @@ +; 29000 mpn_sub_n -- Subtract two limb vectors of the same length > 0 and +; store difference in a third limb vector. + +; Copyright 1992, 1994, 2000 Free Software Foundation, Inc. + +; This file is part of the GNU MP Library. + +; The GNU MP Library is free software; you can redistribute it and/or modify +; it under the terms of the GNU Lesser General Public License as published by +; the Free Software Foundation; either version 3 of the License, or (at your +; option) any later version. + +; The GNU MP Library is distributed in the hope that it will be useful, but +; WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY +; or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public +; License for more details. + +; You should have received a copy of the GNU Lesser General Public License +; along with the GNU MP Library. If not, see http://www.gnu.org/licenses/. + + +; INPUT PARAMETERS +; res_ptr lr2 +; s1_ptr lr3 +; s2_ptr lr4 +; size lr5 + +; We use the loadm/storem instructions and operate on chunks of 8 +; limbs/per iteration, until less than 8 limbs remain. + +; The 29k has no addition or subtraction instructions that doesn't +; affect carry, so we need to save and restore that as soon as we +; adjust the pointers. gr116 is used for this purpose. Note that +; gr116==0 means that carry should be set. + + .sect .lit,lit + .text + .align 4 + .global ___gmpn_sub_n + .word 0x60000 +___gmpn_sub_n: + srl gr117,lr5,3 + sub gr118,gr117,1 + jmpt gr118,Ltail + constn gr116,-1 ; init cy reg + sub gr117,gr117,2 ; count for jmpfdec + +; Main loop working 8 limbs/iteration. +Loop: mtsrim cr,(8-1) + loadm 0,0,gr96,lr3 + add lr3,lr3,32 + mtsrim cr,(8-1) + loadm 0,0,gr104,lr4 + add lr4,lr4,32 + + subr gr116,gr116,0 ; restore carry + subc gr96,gr96,gr104 + subc gr97,gr97,gr105 + subc gr98,gr98,gr106 + subc gr99,gr99,gr107 + subc gr100,gr100,gr108 + subc gr101,gr101,gr109 + subc gr102,gr102,gr110 + subc gr103,gr103,gr111 + subc gr116,gr116,gr116 ; gr116 = not(cy) + + mtsrim cr,(8-1) + storem 0,0,gr96,lr2 + jmpfdec gr117,Loop + add lr2,lr2,32 + +; Code for the last up-to-7 limbs. +; This code might look very strange, but it's hard to write it +; differently without major slowdown. + + and lr5,lr5,(8-1) +Ltail: sub gr118,lr5,1 ; count for CR + jmpt gr118,Lend + sub gr117,lr5,2 ; count for jmpfdec + + mtsr cr,gr118 + loadm 0,0,gr96,lr3 + mtsr cr,gr118 + loadm 0,0,gr104,lr4 + + subr gr116,gr116,0 ; restore carry + + jmpfdec gr117,L1 + subc gr96,gr96,gr104 + jmp Lstore + mtsr cr,gr118 +L1: jmpfdec gr117,L2 + subc gr97,gr97,gr105 + jmp Lstore + mtsr cr,gr118 +L2: jmpfdec gr117,L3 + subc gr98,gr98,gr106 + jmp Lstore + mtsr cr,gr118 +L3: jmpfdec gr117,L4 + subc gr99,gr99,gr107 + jmp Lstore + mtsr cr,gr118 +L4: jmpfdec gr117,L5 + subc gr100,gr100,gr108 + jmp Lstore + mtsr cr,gr118 +L5: jmpfdec gr117,L6 + subc gr101,gr101,gr109 + jmp Lstore + mtsr cr,gr118 +L6: subc gr102,gr102,gr110 + +Lstore: storem 0,0,gr96,lr2 + subc gr116,gr116,gr116 ; gr116 = not(cy) + +Lend: jmpi lr0 + add gr96,gr116,1 |