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dnl x86 mpn_divrem_2 -- Divide an mpn number by a normalized 2-limb number.
dnl Copyright 2007, 2008 Free Software Foundation, Inc.
dnl This file is part of the GNU MP Library.
dnl
dnl The GNU MP Library is free software; you can redistribute it and/or modify
dnl it under the terms of either:
dnl
dnl * the GNU Lesser General Public License as published by the Free
dnl Software Foundation; either version 3 of the License, or (at your
dnl option) any later version.
dnl
dnl or
dnl
dnl * the GNU General Public License as published by the Free Software
dnl Foundation; either version 2 of the License, or (at your option) any
dnl later version.
dnl
dnl or both in parallel, as here.
dnl
dnl The GNU MP Library is distributed in the hope that it will be useful, but
dnl WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
dnl or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
dnl for more details.
dnl
dnl You should have received copies of the GNU General Public License and the
dnl GNU Lesser General Public License along with the GNU MP Library. If not,
dnl see https://www.gnu.org/licenses/.
include(`../config.m4')
C norm frac
C 486
C P5
C P6-13 29.2
C P6-15 *26
C K6
C K7 22
C K8 *19
C P4-f1
C P4-f2 *65
C P4-f3
C P4-f4 *72
C A star means numbers not updated for the latest version of the code.
C TODO
C * Perhaps keep ecx or esi in stack slot, freeing up a reg for q0.
C * The loop has not been carefully tuned. We should at the very least do
C some local insn swapping.
C * The code outside the main loop is what gcc generated. Clean up!
C * Clean up stack slot usage.
C INPUT PARAMETERS
C qp
C fn
C up_param
C un_param
C dp
C eax ebx ecx edx esi edi ebp
C cnt qp
ASM_START()
TEXT
ALIGN(16)
PROLOGUE(mpn_divrem_2)
push %ebp
push %edi
push %esi
push %ebx
sub $36, %esp
mov 68(%esp), %ecx C un
mov 72(%esp), %esi C dp
movl $0, 32(%esp)
lea 0(,%ecx,4), %edi
add 64(%esp), %edi C up
mov (%esi), %ebx
mov 4(%esi), %eax
mov %ebx, 20(%esp)
sub $12, %edi
mov %eax, 24(%esp)
mov %edi, 12(%esp)
mov 8(%edi), %ebx
mov 4(%edi), %ebp
cmp %eax, %ebx
jb L(8)
seta %dl
cmp 20(%esp), %ebp
setae %al
orb %dl, %al C "orb" form to placate Sun tools
jne L(35)
L(8):
mov 60(%esp), %esi C fn
lea -3(%esi,%ecx), %edi
test %edi, %edi
js L(9)
mov 24(%esp), %edx
mov $-1, %esi
mov %esi, %eax
mov %esi, %ecx
not %edx
divl 24(%esp)
mov %eax, %esi
imul 24(%esp), %eax
mov %eax, (%esp)
mov %esi, %eax
mull 20(%esp)
mov (%esp), %eax
add 20(%esp), %eax
adc $0, %ecx
add %eax, %edx
adc $0, %ecx
mov %ecx, %eax
js L(32)
L(36): dec %esi
sub 24(%esp), %edx
sbb $0, %eax
jns L(36)
L(32):
mov %esi, 16(%esp) C di
mov %edi, %ecx C un
mov 12(%esp), %esi C up
mov 24(%esp), %eax
neg %eax
mov %eax, 4(%esp) C -d1
ALIGN(16)
nop
C eax ebx ecx edx esi edi ebp 0 4 8 12 16 20 24 28 32 56 60
C n2 un up n1 q0 -d1 di d0 d1 msl qp fn
L(loop):
mov 16(%esp), %eax C di
mul %ebx
add %ebp, %eax
mov %eax, (%esp) C q0
adc %ebx, %edx
mov %edx, %edi C q
imul 4(%esp), %edx
mov 20(%esp), %eax
lea (%edx, %ebp), %ebx C n1 -= ...
mul %edi
xor %ebp, %ebp
cmp 60(%esp), %ecx
jl L(19)
mov (%esi), %ebp
sub $4, %esi
L(19): sub 20(%esp), %ebp
sbb 24(%esp), %ebx
sub %eax, %ebp
sbb %edx, %ebx
mov 20(%esp), %eax C d1
inc %edi
xor %edx, %edx
cmp (%esp), %ebx
adc $-1, %edx C mask
add %edx, %edi C q--
and %edx, %eax C d0 or 0
and 24(%esp), %edx C d1 or 0
add %eax, %ebp
adc %edx, %ebx
cmp 24(%esp), %ebx
jae L(fix)
L(bck): mov 56(%esp), %edx
mov %edi, (%edx, %ecx, 4)
dec %ecx
jns L(loop)
L(9): mov 64(%esp), %esi C up
mov %ebp, (%esi)
mov %ebx, 4(%esi)
mov 32(%esp), %eax
add $36, %esp
pop %ebx
pop %esi
pop %edi
pop %ebp
ret
L(fix): seta %dl
cmp 20(%esp), %ebp
setae %al
orb %dl, %al C "orb" form to placate Sun tools
je L(bck)
inc %edi
sub 20(%esp), %ebp
sbb 24(%esp), %ebx
jmp L(bck)
L(35): sub 20(%esp), %ebp
sbb 24(%esp), %ebx
movl $1, 32(%esp)
jmp L(8)
EPILOGUE()
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