iPXE
x86_bigint.c
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1 /*
2  * Copyright (C) 2012 Michael Brown <mbrown@fensystems.co.uk>.
3  *
4  * This program is free software; you can redistribute it and/or
5  * modify it under the terms of the GNU General Public License as
6  * published by the Free Software Foundation; either version 2 of the
7  * License, or any later version.
8  *
9  * This program is distributed in the hope that it will be useful, but
10  * WITHOUT ANY WARRANTY; without even the implied warranty of
11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12  * General Public License for more details.
13  *
14  * You should have received a copy of the GNU General Public License
15  * along with this program; if not, write to the Free Software
16  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
17  * 02110-1301, USA.
18  *
19  * You can also choose to distribute this program under the terms of
20  * the Unmodified Binary Distribution Licence (as given in the file
21  * COPYING.UBDL), provided that you have satisfied its requirements.
22  */
23 
24 FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
25 
26 #include <stdint.h>
27 #include <string.h>
28 #include <ipxe/bigint.h>
29 
30 /** @file
31  *
32  * Big integer support
33  */
34 
35 /**
36  * Multiply big integers
37  *
38  * @v multiplicand0 Element 0 of big integer to be multiplied
39  * @v multiplier0 Element 0 of big integer to be multiplied
40  * @v result0 Element 0 of big integer to hold result
41  * @v size Number of elements
42  */
43 void bigint_multiply_raw ( const uint32_t *multiplicand0,
44  const uint32_t *multiplier0,
45  uint32_t *result0, unsigned int size ) {
46  const bigint_t ( size ) __attribute__ (( may_alias )) *multiplicand =
47  ( ( const void * ) multiplicand0 );
48  const bigint_t ( size ) __attribute__ (( may_alias )) *multiplier =
49  ( ( const void * ) multiplier0 );
50  bigint_t ( size * 2 ) __attribute__ (( may_alias )) *result =
51  ( ( void * ) result0 );
52  unsigned int i;
53  unsigned int j;
54  uint32_t multiplicand_element;
55  uint32_t multiplier_element;
56  uint32_t *result_elements;
57  uint32_t discard_a;
58  uint32_t discard_d;
59  long index;
60 
61  /* Zero result */
62  memset ( result, 0, sizeof ( *result ) );
63 
64  /* Multiply integers one element at a time */
65  for ( i = 0 ; i < size ; i++ ) {
66  multiplicand_element = multiplicand->element[i];
67  for ( j = 0 ; j < size ; j++ ) {
68  multiplier_element = multiplier->element[j];
69  result_elements = &result->element[ i + j ];
70  /* Perform a single multiply, and add the
71  * resulting double-element into the result,
72  * carrying as necessary. The carry can
73  * never overflow beyond the end of the
74  * result, since:
75  *
76  * a < 2^{n}, b < 2^{n} => ab < 2^{2n}
77  */
78  __asm__ __volatile__ ( "mull %4\n\t"
79  "addl %%eax, (%5,%2,4)\n\t"
80  "adcl %%edx, 4(%5,%2,4)\n\t"
81  "\n1:\n\t"
82  "adcl $0, 8(%5,%2,4)\n\t"
83  "inc %2\n\t"
84  /* Does not affect CF */
85  "jc 1b\n\t"
86  : "=&a" ( discard_a ),
87  "=&d" ( discard_d ),
88  "=&r" ( index )
89  : "0" ( multiplicand_element ),
90  "g" ( multiplier_element ),
91  "r" ( result_elements ),
92  "2" ( 0 ) );
93  }
94  }
95 }
#define __attribute__(x)
Definition: compiler.h:10
FILE_LICENCE(GPL2_OR_LATER_OR_UBDL)
uint8_t multiplier
Port multiplier number.
Definition: edd.h:32
Big integer support.
int result
Definition: bigint.h:148
void bigint_multiply_raw(const uint32_t *multiplicand0, const uint32_t *multiplier0, uint32_t *result0, unsigned int size)
Multiply big integers.
Definition: x86_bigint.c:43
const bigint_t(size) __attribute__((may_alias)) *reference
unsigned int uint32_t
Definition: stdint.h:12
__asm__ __volatile__("\n1:\n\t" "movb -1(%2,%1), %%al\n\t" "stosb\n\t" "loop 1b\n\t" "xorl %%eax, %%eax\n\t" "mov %3, %1\n\t" "rep stosb\n\t" :"=&D"(discard_D), "=&c"(discard_c) :"r"(data), "g"(pad_len), "0"(value0), "1"(len) :"eax")
__asm__(".section \".rodata\", \"a\", " PROGBITS "\n\t" "\nprivate_key_data:\n\t" ".size private_key_data, ( . - private_key_data )\n\t" ".equ private_key_len, ( . - private_key_data )\n\t" ".previous\n\t")
uint8_t size
Entry size (in 32-bit words)
Definition: ena.h:16
uint64_t index
Index of the first segment within the content.
Definition: pccrc.h:21
String functions.
void * memset(void *dest, int character, size_t len) __nonnull