1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
|
// $OpenBSD: bignum_mul_4_8.S,v 1.4 2025/08/12 10:23:40 jsing Exp $
//
// Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
//
// Permission to use, copy, modify, and/or distribute this software for any
// purpose with or without fee is hereby granted, provided that the above
// copyright notice and this permission notice appear in all copies.
//
// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
// WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
// MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
// ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
// WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
// ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
// OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
// ----------------------------------------------------------------------------
// Multiply z := x * y
// Inputs x[4], y[4]; output z[8]
//
// extern void bignum_mul_4_8(uint64_t z[static 8], const uint64_t x[static 4],
// const uint64_t y[static 4]);
//
// Standard x86-64 ABI: RDI = z, RSI = x, RDX = y
// Microsoft x64 ABI: RCX = z, RDX = x, R8 = y
// ----------------------------------------------------------------------------
#include "s2n_bignum_internal.h"
.intel_syntax noprefix
S2N_BN_SYM_VISIBILITY_DIRECTIVE(bignum_mul_4_8)
S2N_BN_SYM_PRIVACY_DIRECTIVE(bignum_mul_4_8)
.text
// These are actually right
#define z rdi
#define x rsi
// Copied in or set up
#define y rcx
// A zero register
#define zero rbp
#define zeroe ebp
// Add in x[i] * rdx to the (i,i+1) position with the register window
// Would be nice to have conditional expressions reg[i], reg[i+1] ...
.macro mulpadd arg1,arg2
mulx rbx, rax, [x+8*\arg2]
.if ((\arg1 + \arg2) % 4 == 0)
adcx r8, rax
adox r9, rbx
.elseif ((\arg1 + \arg2) % 4 == 1)
adcx r9, rax
adox r10, rbx
.elseif ((\arg1 + \arg2) % 4 == 2)
adcx r10, rax
adox r11, rbx
.elseif ((\arg1 + \arg2) % 4 == 3)
adcx r11, rax
adox r8, rbx
.endif
.endm
// Add in the whole j'th row
.macro addrow arg1
mov rdx, [y+8*\arg1]
xor zeroe, zeroe
mulpadd \arg1, 0
.if (\arg1 % 4 == 0)
mov [z+8*\arg1],r8
.elseif (\arg1 % 4 == 1)
mov [z+8*\arg1],r9
.elseif (\arg1 % 4 == 2)
mov [z+8*\arg1],r10
.elseif (\arg1 % 4 == 3)
mov [z+8*\arg1],r11
.endif
mulpadd \arg1, 1
mulpadd \arg1, 2
.if (\arg1 % 4 == 0)
mulx r8, rax, [x+24]
adcx r11, rax
adox r8, zero
adcx r8, zero
.elseif (\arg1 % 4 == 1)
mulx r9, rax, [x+24]
adcx r8, rax
adox r9, zero
adcx r9, zero
.elseif (\arg1 % 4 == 2)
mulx r10, rax, [x+24]
adcx r9, rax
adox r10, zero
adcx r10, zero
.elseif (\arg1 % 4 == 3)
mulx r11, rax, [x+24]
adcx r10, rax
adox r11, zero
adcx r11, zero
.endif
.endm
S2N_BN_SYMBOL(bignum_mul_4_8):
_CET_ENDBR
#if WINDOWS_ABI
push rdi
push rsi
mov rdi, rcx
mov rsi, rdx
mov rdx, r8
#endif
// Save more registers to play with
push rbp
push rbx
// Copy y into a safe register to start with
mov y, rdx
// Zero a register, which also makes sure we don't get a fake carry-in
xor zeroe, zeroe
// Do the zeroth row, which is a bit different
// Write back the zero-zero product and then accumulate
// r8,r11,r10,r9 as y[0] * x from 1..4
mov rdx, [y]
mulx r9, r8, [x]
mov [z], r8
mulx r10, rbx, [x+8]
adcx r9, rbx
mulx r11, rbx, [x+16]
adcx r10, rbx
mulx r8, rbx, [x+24]
adcx r11, rbx
adcx r8, zero
// Now all the other rows in a uniform pattern
addrow 1
addrow 2
addrow 3
// Now write back the additional columns
mov [z+32], r8
mov [z+40], r9
mov [z+48], r10
mov [z+56], r11
// Restore registers and return
pop rbx
pop rbp
#if WINDOWS_ABI
pop rsi
pop rdi
#endif
ret
#if defined(__linux__) && defined(__ELF__)
.section .note.GNU-stack,"",%progbits
#endif
|
