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Diffstat (limited to 'sysdeps/m88k/sub_n.s')
| -rw-r--r-- | sysdeps/m88k/sub_n.s | 104 |
1 files changed, 104 insertions, 0 deletions
diff --git a/sysdeps/m88k/sub_n.s b/sysdeps/m88k/sub_n.s new file mode 100644 index 0000000000..3963cd5479 --- /dev/null +++ b/sysdeps/m88k/sub_n.s @@ -0,0 +1,104 @@ +; mc88100 __mpn_sub -- Subtract two limb vectors of the same length > 0 and +; store difference in a third limb vector. + +; Copyright (C) 1992, 1994 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 Library General Public License as published by +; the Free Software Foundation; either version 2 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 Library General Public +; License for more details. + +; You should have received a copy of the GNU Library General Public License +; along with the GNU MP Library; see the file COPYING.LIB. If not, write to +; the Free Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. + + +; INPUT PARAMETERS +; res_ptr r2 +; s1_ptr r3 +; s2_ptr r4 +; size r5 + +; This code has been optimized to run one instruction per clock, avoiding +; load stalls and writeback contention. As a result, the instruction +; order is not always natural. + +; The speed is about 4.6 clocks/limb + 18 clocks/limb-vector on an 88100, +; but on the 88110, it seems to run much slower, 6.6 clocks/limb. + + text + align 16 + global ___mpn_sub_n +___mpn_sub_n: + ld r6,r3,0 ; read first limb from s1_ptr + extu r10,r5,3 + ld r7,r4,0 ; read first limb from s2_ptr + + subu.co r5,r0,r5 ; (clear carry as side effect) + mak r5,r5,3<4> + bcnd eq0,r5,Lzero + + or r12,r0,lo16(Lbase) + or.u r12,r12,hi16(Lbase) + addu r12,r12,r5 ; r12 is address for entering in loop + + extu r5,r5,2 ; divide by 4 + subu r2,r2,r5 ; adjust res_ptr + subu r3,r3,r5 ; adjust s1_ptr + subu r4,r4,r5 ; adjust s2_ptr + + or r8,r6,r0 + + jmp.n r12 + or r9,r7,r0 + +Loop: addu r3,r3,32 + st r8,r2,28 + addu r4,r4,32 + ld r6,r3,0 + addu r2,r2,32 + ld r7,r4,0 +Lzero: subu r10,r10,1 ; subtract 0 + 8r limbs (adj loop cnt) +Lbase: ld r8,r3,4 + subu.cio r6,r6,r7 + ld r9,r4,4 + st r6,r2,0 + ld r6,r3,8 ; subtract 7 + 8r limbs + subu.cio r8,r8,r9 + ld r7,r4,8 + st r8,r2,4 + ld r8,r3,12 ; subtract 6 + 8r limbs + subu.cio r6,r6,r7 + ld r9,r4,12 + st r6,r2,8 + ld r6,r3,16 ; subtract 5 + 8r limbs + subu.cio r8,r8,r9 + ld r7,r4,16 + st r8,r2,12 + ld r8,r3,20 ; subtract 4 + 8r limbs + subu.cio r6,r6,r7 + ld r9,r4,20 + st r6,r2,16 + ld r6,r3,24 ; subtract 3 + 8r limbs + subu.cio r8,r8,r9 + ld r7,r4,24 + st r8,r2,20 + ld r8,r3,28 ; subtract 2 + 8r limbs + subu.cio r6,r6,r7 + ld r9,r4,28 + st r6,r2,24 + bcnd.n ne0,r10,Loop ; subtract 1 + 8r limbs + subu.cio r8,r8,r9 + + st r8,r2,28 ; store most significant limb + + addu.ci r2,r0,r0 ; return carry-out from most sign. limb + jmp.n r1 + xor r2,r2,1 |