346 lines
9.9 KiB
NASM
346 lines
9.9 KiB
NASM
; PROLOGUE(mpn_karasub)
|
|
; mpn_karasub
|
|
;
|
|
; Copyright 2011 The Code Cavern
|
|
;
|
|
; Copyright 2012 Brian Gladman
|
|
;
|
|
; This file is part of the MPIR Library.
|
|
;
|
|
; The MPIR 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 MPIR 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 MPIR Library; see the file COPYING.LIB. If not, write
|
|
; to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
|
|
; Boston, MA 02110-1301, USA.
|
|
;
|
|
; void mpn_karasub(mp_ptr, mp_ptr, mp_size_t)
|
|
; rax rdi rsi rdx
|
|
; rax rcx rdx r8
|
|
;
|
|
; Karasuba Multiplication - split x and y into two equal length halves so
|
|
; that x = xh.B + xl and y = yh.B + yl. Then their product is:
|
|
;
|
|
; x.y = xh.yh.B^2 + (xh.yl + xl.yh).B + xl.yl
|
|
; = xh.yh.B^2 + (xh.yh + xl.yl - {xh - xl}.{yh - yl}).B + xl.yl
|
|
;
|
|
; If the length of the elements is m (about n / 2), the output length is 4 * m
|
|
; as illustrated below. The middle two blocks involve three additions and one
|
|
; subtraction:
|
|
;
|
|
; -------------------- rp
|
|
; | |-->
|
|
; | A:xl.yl[lo] | |
|
|
; | | | (xh - xl).(yh - yl)
|
|
; -------------------- | -------------------- tp
|
|
; <-- | |<--< <-- | |
|
|
; | | B:xl.yl[hi] | | | E:[lo] |
|
|
; | | | | | |
|
|
; | -------------------- | --------------------
|
|
; >--> | |--> <-- | |
|
|
; |\___ | C:xh.yh[lo] | ____/ | F:[hi] |
|
|
; | | | | |
|
|
; | -------------------- --------------------
|
|
; <-- | |
|
|
; | D:xh.yh[hi] |
|
|
; | |
|
|
; --------------------
|
|
;
|
|
; To avoid overwriting B before it is used, we need to do two operations
|
|
; in parallel:
|
|
;
|
|
; (1) B = B + C + A - E = (B + C) + A - E
|
|
; (2) C = C + B + D - F = (B + C) + D - F
|
|
;
|
|
; The final carry from (1) has to be propagated into C and D, and the final
|
|
; carry from (2) has to be propagated into D. When the number of input limbs
|
|
; is odd, some extra operations have to be undertaken.
|
|
|
|
%include "yasm_mac.inc"
|
|
|
|
%define reg_save_list rbx, rbp, rsi, rdi, r12, r13, r14, r15
|
|
|
|
%macro add_one 1
|
|
inc %1
|
|
%endmacro
|
|
|
|
BITS 64
|
|
TEXT
|
|
|
|
; requires n >= 8
|
|
FRAME_PROC mpn_karasub, 2, reg_save_list
|
|
mov rdi, rcx
|
|
mov rsi, rdx
|
|
mov rdx, r8
|
|
mov [rsp], rdx
|
|
mov [rsp+8], rdi
|
|
|
|
; rp is rdi, tp is rsi, L is rdi, H is rbp, tp is rsi
|
|
; carries/borrows in rax, rbx
|
|
|
|
shr rdx, 1
|
|
lea rcx, [rdx+rdx*1]
|
|
lea rbp, [rdi+rcx*8]
|
|
xor rax, rax
|
|
xor rbx, rbx
|
|
lea rdi, [rdi+rdx*8-24]
|
|
lea rsi, [rsi+rdx*8-24]
|
|
lea rbp, [rbp+rdx*8-24]
|
|
mov ecx, 3
|
|
sub rcx, rdx
|
|
mov edx, 3
|
|
|
|
align 16
|
|
.1: bt rbx, 2
|
|
mov r8, [rdi+rdx*8]
|
|
adc r8, [rbp+rcx*8]
|
|
mov r12, r8
|
|
mov r9, [rdi+rdx*8+8]
|
|
adc r9, [rbp+rcx*8+8]
|
|
mov r10, [rdi+rdx*8+16]
|
|
adc r10, [rbp+rcx*8+16]
|
|
mov r11, [rdi+rdx*8+24]
|
|
adc r11, [rbp+rcx*8+24]
|
|
rcl rbx, 1
|
|
bt rax, 1
|
|
mov r15, r11
|
|
adc r8, [rdi+rcx*8]
|
|
mov r13, r9
|
|
adc r9, [rdi+rcx*8+8]
|
|
mov r14, r10
|
|
adc r10, [rdi+rcx*8+16]
|
|
adc r11, [rdi+rcx*8+24]
|
|
rcl rax, 1
|
|
bt rbx, 2
|
|
adc r12, [rbp+rdx*8]
|
|
adc r13, [rbp+rdx*8+8]
|
|
adc r14, [rbp+rdx*8+16]
|
|
adc r15, [rbp+rdx*8+24]
|
|
rcl rbx, 1
|
|
bt rax, 1
|
|
sbb r8, [rsi+rcx*8]
|
|
sbb r9, [rsi+rcx*8+8]
|
|
sbb r10, [rsi+rcx*8+16]
|
|
sbb r11, [rsi+rcx*8+24]
|
|
mov [rdi+rdx*8+16], r10
|
|
mov [rdi+rdx*8+24], r11
|
|
rcl rax, 1
|
|
bt rbx, 2
|
|
mov [rdi+rdx*8], r8
|
|
mov [rdi+rdx*8+8], r9
|
|
sbb r12, [rsi+rdx*8]
|
|
sbb r13, [rsi+rdx*8+8]
|
|
sbb r14, [rsi+rdx*8+16]
|
|
sbb r15, [rsi+rdx*8+24]
|
|
rcl rbx, 1
|
|
add rdx, 4
|
|
mov [rbp+rcx*8], r12
|
|
mov [rbp+rcx*8+8], r13
|
|
mov [rbp+rcx*8+16], r14
|
|
mov [rbp+rcx*8+24], r15
|
|
add rcx, 4
|
|
jnc .1
|
|
cmp rcx, 2
|
|
jg .5
|
|
jz .4
|
|
jp .3
|
|
|
|
.2: bt rbx, 2
|
|
mov r8, [rdi+rdx*8]
|
|
adc r8, [rbp]
|
|
mov r12, r8
|
|
mov r9, [rdi+rdx*8+8]
|
|
adc r9, [rbp+8]
|
|
mov r10, [rdi+rdx*8+16]
|
|
adc r10, [rbp+16]
|
|
rcl rbx, 1
|
|
bt rax, 1
|
|
adc r8, [rdi]
|
|
mov r13, r9
|
|
adc r9, [rdi+8]
|
|
mov r14, r10
|
|
adc r10, [rdi+16]
|
|
rcl rax, 1
|
|
bt rbx, 2
|
|
adc r12, [rbp+rdx*8]
|
|
adc r13, [rbp+rdx*8+8]
|
|
adc r14, [rbp+rdx*8+16]
|
|
rcl rbx, 1
|
|
bt rax, 1
|
|
sbb r8, [rsi]
|
|
sbb r9, [rsi+8]
|
|
sbb r10, [rsi+16]
|
|
mov [rdi+rdx*8+16], r10
|
|
rcl rax, 1
|
|
bt rbx, 2
|
|
mov [rdi+rdx*8], r8
|
|
mov [rdi+rdx*8+8], r9
|
|
sbb r12, [rsi+rdx*8]
|
|
sbb r13, [rsi+rdx*8+8]
|
|
sbb r14, [rsi+rdx*8+16]
|
|
rcl rbx, 1
|
|
add rdx, 3
|
|
mov [rbp], r12
|
|
mov [rbp+8], r13
|
|
mov [rbp+16], r14
|
|
jmp .5
|
|
|
|
.3: bt rbx, 2
|
|
mov r8, [rdi+rdx*8]
|
|
adc r8, [rbp+8]
|
|
mov r12, r8
|
|
mov r9, [rdi+rdx*8+8]
|
|
adc r9, [rbp+16]
|
|
rcl rbx, 1
|
|
bt rax, 1
|
|
adc r8, [rdi+8]
|
|
mov r13, r9
|
|
adc r9, [rdi+16]
|
|
rcl rax, 1
|
|
bt rbx, 2
|
|
adc r12, [rbp+rdx*8]
|
|
adc r13, [rbp+rdx*8+8]
|
|
rcl rbx, 1
|
|
bt rax, 1
|
|
sbb r8, [rsi+8]
|
|
sbb r9, [rsi+16]
|
|
rcl rax, 1
|
|
bt rbx, 2
|
|
mov [rdi+rdx*8], r8
|
|
mov [rdi+rdx*8+8], r9
|
|
sbb r12, [rsi+rdx*8]
|
|
sbb r13, [rsi+rdx*8+8]
|
|
rcl rbx, 1
|
|
add rdx, 2
|
|
mov [rbp+8], r12
|
|
mov [rbp+16], r13
|
|
jmp .5
|
|
|
|
.4: bt rbx, 2
|
|
mov r8, [rdi+rdx*8]
|
|
adc r8, [rbp+16]
|
|
mov r12, r8
|
|
rcl rbx, 1
|
|
bt rax, 1
|
|
adc r8, [rdi+16]
|
|
rcl rax, 1
|
|
bt rbx, 2
|
|
adc r12, [rbp+rdx*8]
|
|
rcl rbx, 1
|
|
bt rax, 1
|
|
sbb r8, [rsi+16]
|
|
rcl rax, 1
|
|
bt rbx, 2
|
|
mov [rdi+rdx*8], r8
|
|
sbb r12, [rsi+rdx*8]
|
|
rcl rbx, 1
|
|
add_one rdx
|
|
mov [rbp+rcx*8], r12
|
|
|
|
; move low half rbx carry into rax
|
|
.5: rcr rax, 3
|
|
bt rbx, 2
|
|
rcl rax, 3
|
|
mov r8, [rsp]
|
|
mov rcx, rsi
|
|
mov rsi,[rsp+8]
|
|
lea r9, [r8+r8]
|
|
lea rsi, [rsi+r9*8]
|
|
lea r11, [rbp+24]
|
|
sub r11, rsi
|
|
sar r11, 3
|
|
bt r8, 0
|
|
jnc .9
|
|
|
|
; if odd the do next two
|
|
add r11, 2
|
|
mov r8, [rbp+rdx*8]
|
|
mov r9, [rbp+rdx*8+8]
|
|
rcr rbx, 2
|
|
adc r8,0
|
|
adc r9, 0
|
|
rcl rbx, 1
|
|
sbb r8, [rcx+rdx*8]
|
|
sbb r9, [rcx+rdx*8+8]
|
|
rcr rbx, 2
|
|
adc [rbp+24], r8
|
|
adc [rbp+32], r9
|
|
rcl rbx, 3
|
|
|
|
; Now add in any accummulated carries and/or borrows
|
|
;
|
|
; NOTE: We can't propagate individual borrows or carries from the second
|
|
; and third quarter blocks into the fourth quater block by simply waiting
|
|
; for carry (or borrow) propagation to end. This is because a carry into
|
|
; the fourth quarter block when it contains only maximum integers or a
|
|
; borrow when it contains all zero integers will incorrectly propagate
|
|
; beyond the end of the top quarter block.
|
|
|
|
.9: lea rdx, [rdi+rdx*8]
|
|
sub rdx, rsi
|
|
sar rdx, 3
|
|
|
|
; carries/borrrow from second to third quarter quarter block
|
|
; rax{2} is the carry in (B + C)
|
|
; rax{1} is the carry in (B + C) + A
|
|
; rax{0} is the borrow in (B + C + A) - E
|
|
|
|
mov rcx, rdx
|
|
bt rax, 0
|
|
.10: sbb qword[rsi+rcx*8], 0
|
|
add_one rcx
|
|
jrcxz .11
|
|
jc .10
|
|
|
|
.11 mov rcx, rdx
|
|
bt rax, 1
|
|
.12: adc qword[rsi+rcx*8], 0
|
|
add_one rcx
|
|
jrcxz .13
|
|
jc .12
|
|
|
|
.13 mov rcx, rdx
|
|
bt rax, 2
|
|
.14: adc qword[rsi+rcx*8], 0
|
|
add_one rcx
|
|
jrcxz .15
|
|
jc .14
|
|
|
|
; carries/borrrow from third to fourth quarter quarter block
|
|
; rbx{2} is the carry in (B + C)
|
|
; rbx{1} is the carry in (B + C) + D
|
|
; rbx{0} is the borrow in (B + C + D) - F
|
|
|
|
.15: mov rcx, r11
|
|
bt rbx, 0
|
|
.16: sbb qword[rsi+rcx*8], 0
|
|
add_one rcx
|
|
jrcxz .17
|
|
jc .16
|
|
|
|
.17: mov rcx, r11
|
|
bt rbx, 1
|
|
.18: adc qword[rsi+rcx*8], 0
|
|
add_one rcx
|
|
jrcxz .19
|
|
jc .18
|
|
|
|
.19: mov rcx, r11
|
|
bt rbx, 2
|
|
.20: adc qword[rsi+rcx*8], 0
|
|
add_one rcx
|
|
jrcxz .21
|
|
jc .20
|
|
.21:
|
|
END_PROC reg_save_list
|
|
|
|
end
|