/* bigint_asm.S */
/*
This file is part of the ARM-Crypto-Lib.
Copyright (C) 2006-2010 Daniel Otte (daniel.otte@rub.de)
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program 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 General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see .
*/
#include "avr-asm-macros.S"
#include "bigint_adjust.S"
#include "bigint_add_u.S"
/******************************************************************************/
/*
void bigint_add_scale_u(bigint_t* dest, const bigint_t* a, uint16_t scale){
uint16_t i,j=0;
uint16_t t=0;
if(scale>dest->length_B)
memset(dest->wordv+dest->length_B, 0, scale-dest->length_B);
for(i=scale; ilength_B+scale; ++i,++j){
t = a->wordv[j] + t;
if(dest->length_B>i){
t += dest->wordv[i];
}
dest->wordv[i] = (uint8_t)t;
t>>=8;
}
while(t){
if(dest->length_B>i){
t = dest->wordv[i] + t;
}
dest->wordv[i] = (uint8_t)t;
t>>=8;
++i;
}
if(dest->length_B < i){
dest->length_B = i;
}
bigint_adjust(dest);
}
*/
DST_SIZE_0 = 22
DST_SIZE_1 = 23
SRC_SIZE_0 = 20
SRC_SIZE_1 = 23
SCALE_0 = 18
SCALE_1 = 19
DST_CTX_0 = 6
DST_CTX_1 = 7
SRC_CTX_0 = 8
SRC_CTX_1 = 9
TMP_0 = 10
TMP_1 = 11
.global bigint_add_scale_u
#if 0
bigint_add_scale_u:
push_range 6, 11
movw r30, r24 /* dest ptr */
movw r26, r22 /* src ptr */
movw r24, r20 /* scale */
movw DST_CTX_0, r30
movw SRC_CTX_0, r26
movw SCALE_0, r24
/* pad dst with zeros if scale > dst_length */
ld DST_SIZE_0, Z+
ld DST_SIZE_1, Z+
sub r24, DST_SIZE_0
sbc r25, DST_SIZE_1
ldd TMP_0, Z+1 /* load tmp with DST_WORDV */
ldd TMP_1, Z+2
movw r30, TMP_0
brmi 20f /* branch if DST_SIZE > scale */
add r30, DST_SIZE_0
adc r31, DST_SIZE_1
10:
sbiw r24, 1
brmi 25f
st Z+, r1
rjmp 10b
20:
add r30, r20 /* add scale to DST_WORDV */
adc r31, r21
/* add src to dest until one of the two ends */
25:
ld SRC_SIZE_0, X+
ld SRC_SIZE_1, X+
adiw r26, 1
ld TMP_0, X+ /* load tmp with SRC_WORDV */
ld TMP_1, X
movw r26, TMP_0
movw r24, SRC_SIZE_0
add r24, SCALE_0
adc r25, SCALE_1
clt
cp r24, DST_SIZE_0
cpc r25, DST_SIZE_1
brlo 30f
set
movw r24, DST_SIZE_0
30:
adiw r24, 0
breq 35f
inc r25
clc
31:
ld TMP_0, X+
ld TMP_1, Z
adc TMP_1, TMP_0
st Z+, TMP_1
dec r24
brne 31b
dec r25
brne 31b
35:
rol TMP_1
brts 40f
/* dst is longer than src+scale */
ror TMP_1
38:
ld TMP_0, Z
adc TMP_0, r1
st Z+, TMP_0
brcs 38b
rjmp 90f
40:
/* dst is shorter than src+scale */
movw r24, SRC_SIZE_0
sub r24, DST_SIZE_0
sbc r25, DST_SIZE_1
add r24, SCALE_0
adc r25, SCALE_1
adiw r24, 0
breq 90f
inc r25
ror TMP_1
45:
ld TMP_0, X+
adc TMP_0, r1
st Z+, TMP_0
dec r24
brne 45b
dec r25
brne 45b
90:
movw r24, DST_CTX_0
pop_range 6, 11
rjmp bigint_adjust
#endif
/******************************************************************************/
/******************************************************************************/
/******************************************************************************/
DST_LEN_0 = 22
DST_LEN_1 = 23
SRC_LEN_0 = 20
SRC_LEN_1 = 21
SCALE_0 = 18
SCALE_1 = 19
DST_CTX_0 = 6
DST_CTX_1 = 7
SRC_CTX_0 = 8
SRC_CTX_1 = 9
TMP_0 = 10
TMP_1 = 11
bigint_add_scale_u:
push_range 6, 11
movw r30, r24 /* dest ptr */
movw r26, r22 /* src ptr */
movw r24, r20 /* scale */
movw DST_CTX_0, r30
movw SRC_CTX_0, r26
movw SCALE_0, r24
/* pad dest with zeros to length of SRC_LENGTH + scale */
ld SRC_LEN_0, X+
ld SRC_LEN_1, X+
adiw r26, 1
ld TMP_0, X+
ld TMP_1, X+
movw r26, TMP_0 /* move SRC_WORDV to X */
ldd DST_LEN_0, Z+0
ldd DST_LEN_1, Z+1
ldd TMP_0, Z+3
ldd TMP_1, Z+4
movw r30, TMP_0 /* move DEST_WORDV to Z */
movw TMP_0, SCALE_0
sub TMP_0, DST_LEN_0
sbc TMP_1, DST_LEN_1
movw r24, TMP_0
brmi 40f /* no padding needed since DST_LEN > scale */
add r30, DST_LEN_0 /* add DST_LEN to Z (DEST_WORDV)*/
adc r31, DST_LEN_1
/* pad and copy src in front of dest */
10: /* padding loop */
sbiw r24, 1
brmi 11f
st Z+, r1
rjmp 10b
11:
/* start of copy */
movw r24, SRC_LEN_0
12: /* copy loop */
sbiw r24, 1
brmi 13f
ld TMP_0, X+
st Z+, TMP_0
rjmp 12b
13:
movw TMP_0, SCALE_0
add TMP_0, SRC_LEN_0
adc TMP_1, SRC_LEN_1
movw r30, DST_CTX_0
std Z+0, TMP_0
std Z+1, TMP_1
movw r24, r30
99:
pop_range 6, 11
rjmp bigint_adjust
40:
/* TODO */
/* Z points at DST_WORDV */
/* X points at SRC_WORDV */
/* r24:r25 contains scale - DST_LEN (negativ) */
/* set T bit if DST_LEN > SCR_LEN + scale */
clt
add r30, SCALE_0
adc r31, SCALE_1
add TMP_0, SRC_LEN_0
adc TMP_1, SRC_LEN_1
brpl 41f
set
/* DST_LEN > SRC_LEN + scale && DST_LEN > scale */
/*
+-------+-------+ SRC + scale
+------+------------+ DST
*/
movw r24, SRC_LEN_0
rjmp 44f
41:
/* DST_LEN <= SRC_LEN + scale && DST_LEN > scale */
/*
+-------+-------+ SRC + scale
+------------+ DST
*/
com r24 /* negate r24:r25 */
com r25
adiw r24, 1
44:
clc
45:
dec r24
brpl 46f
dec r25
brmi 50f
46: ld TMP_0, X+
ld TMP_1, Z
adc TMP_0, TMP_1
st Z+, TMP_0
rjmp 45b
50:
/* do the overhaning part */
rol r1
movw r24, r30
movw r30, DST_CTX_0
ldd TMP_0, Z+3
ldd TMP_1, Z+4
movw r30, TMP_0
add r30, DST_LEN_0
adc r31, DST_LEN_1
adiw r30, 1
st Z, r1
movw r30, r24
ror r1
brtc 60f
51: brcc 53f
52: ld TMP_0, Z
adc TMP_0, r1
st Z+, TMP_0
brcs 52b
53:
/* TODO */
movw r24, r30
movw r30, DST_CTX_0
ldd TMP_0, Z+3
ldd TMP_1, Z+4
sub r24, TMP_0
sbc r25, TMP_1
std Z+0, r24
std Z+1, r25
movw r24, r30
rjmp 99b
60: rol r1 /* backup carry */
movw r24, SRC_LEN_0
add r24, SCALE_0
adc r25, SCALE_1
sub r24, DST_LEN_0
sbc r25, DST_LEN_1
ror r1 /* restore carry */
61: dec r24
brpl 62f
dec r25
brmi 63f
62: ld TMP_0, X+
adc TMP_0, r1
st Z+, TMP_0
rjmp 61b
63:
brcc 53b
ldi r24, 1
st Z+, r24
rjmp 53b