--- /dev/null
+; mc88100 __gmpn_mul_1 -- Multiply a limb vector with a single limb and
+; store the product in a second limb vector.
+
+; Copyright (C) 1992, 1994, 1995, 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 2.1 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; see the file COPYING.LIB. If not, write to
+; the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
+; MA 02111-1307, USA.
+
+
+; INPUT PARAMETERS
+; res_ptr r2
+; s1_ptr r3
+; size r4
+; s2_limb r5
+
+; Common overhead is about 11 cycles/invocation.
+
+; The speed for S2_LIMB >= 0x10000 is approximately 21 cycles/limb. (The
+; pipeline stalls 2 cycles due to WB contention.)
+
+; The speed for S2_LIMB < 0x10000 is approximately 16 cycles/limb. (The
+; pipeline stalls 2 cycles due to WB contention and 1 cycle due to latency.)
+
+; To enhance speed:
+; 1. Unroll main loop 4-8 times.
+; 2. Schedule code to avoid WB contention. It might be tempting to move the
+; ld instruction in the loops down to save 2 cycles (less WB contention),
+; but that looses because the ultimate value will be read from outside
+; the allocated space. But if we handle the ultimate multiplication in
+; the tail, we can do this.
+; 3. Make the multiplication with less instructions. I think the code for
+; (S2_LIMB >= 0x10000) is not minimal.
+; With these techniques the (S2_LIMB >= 0x10000) case would run in 17 or
+; less cycles/limb; the (S2_LIMB < 0x10000) case would run in 11
+; cycles/limb. (Assuming infinite unrolling.)
+
+ text
+ align 16
+ global ___gmpn_mul_1
+___gmpn_mul_1:
+
+ ; Make S1_PTR and RES_PTR point at the end of their blocks
+ ; and negate SIZE.
+ lda r3,r3[r4]
+ lda r6,r2[r4] ; RES_PTR in r6 since r2 is retval
+ subu r4,r0,r4
+
+ addu.co r2,r0,r0 ; r2 = cy = 0
+ ld r9,r3[r4]
+ mask r7,r5,0xffff ; r7 = lo(S2_LIMB)
+ extu r8,r5,16 ; r8 = hi(S2_LIMB)
+ bcnd.n eq0,r8,Lsmall ; jump if (hi(S2_LIMB) == 0)
+ subu r6,r6,4
+
+; General code for any value of S2_LIMB.
+
+ ; Make a stack frame and save r25 and r26
+ subu r31,r31,16
+ st.d r25,r31,8
+
+ ; Enter the loop in the middle
+ br.n L1
+ addu r4,r4,1
+
+Loop: ld r9,r3[r4]
+ st r26,r6[r4]
+; bcnd ne0,r0,0 ; bubble
+ addu r4,r4,1
+L1: mul r26,r9,r5 ; low word of product mul_1 WB ld
+ mask r12,r9,0xffff ; r12 = lo(s1_limb) mask_1
+ mul r11,r12,r7 ; r11 = prod_0 mul_2 WB mask_1
+ mul r10,r12,r8 ; r10 = prod_1a mul_3
+ extu r13,r9,16 ; r13 = hi(s1_limb) extu_1 WB mul_1
+ mul r12,r13,r7 ; r12 = prod_1b mul_4 WB extu_1
+ mul r25,r13,r8 ; r25 = prod_2 mul_5 WB mul_2
+ extu r11,r11,16 ; r11 = hi(prod_0) extu_2 WB mul_3
+ addu r10,r10,r11 ; addu_1 WB extu_2
+; bcnd ne0,r0,0 ; bubble WB addu_1
+ addu.co r10,r10,r12 ; WB mul_4
+ mask.u r10,r10,0xffff ; move the 16 most significant bits...
+ addu.ci r10,r10,r0 ; ...to the low half of the word...
+ rot r10,r10,16 ; ...and put carry in pos 16.
+ addu.co r26,r26,r2 ; add old carry limb
+ bcnd.n ne0,r4,Loop
+ addu.ci r2,r25,r10 ; compute new carry limb
+
+ st r26,r6[r4]
+ ld.d r25,r31,8
+ jmp.n r1
+ addu r31,r31,16
+
+; Fast code for S2_LIMB < 0x10000
+Lsmall:
+ ; Enter the loop in the middle
+ br.n SL1
+ addu r4,r4,1
+
+SLoop: ld r9,r3[r4] ;
+ st r8,r6[r4] ;
+ addu r4,r4,1 ;
+SL1: mul r8,r9,r5 ; low word of product
+ mask r12,r9,0xffff ; r12 = lo(s1_limb)
+ extu r13,r9,16 ; r13 = hi(s1_limb)
+ mul r11,r12,r7 ; r11 = prod_0
+ mul r12,r13,r7 ; r12 = prod_1b
+ addu.cio r8,r8,r2 ; add old carry limb
+ extu r10,r11,16 ; r11 = hi(prod_0)
+ addu r10,r10,r12 ;
+ bcnd.n ne0,r4,SLoop
+ extu r2,r10,16 ; r2 = new carry limb
+
+ jmp.n r1
+ st r8,r6[r4]
projects / ghc-hetmet.git / blobdiff