/* bigint_asm.S */
/*
This file is part of the ARM-Crypto-Lib.
- Copyright (C) 2006-2010 Daniel Otte (daniel.otte@rub.de)
+ Copyright (C) 2006-2015 Daniel Otte (bg@nerilex.org)
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
/******************************************************************************/
/*
-void bigint_add_scale_u(bigint_t* dest, const bigint_t* a, uint16_t scale){
+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)
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
/******************************************************************************/
/******************************************************************************/
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
+DST_CTX_0 = 8
+DST_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
+ /* check if scale is zero */
movw SCALE_0, r24
+ adiw r24, 0
+ brne 10f
+ movw r24, r30
+ movw r20, r30
+ rjmp bigint_add_u
+10: /* check if src is zero */
+ ld r24, X+
+ ld r25, X+
+ adiw r24, 0
+ brne 10f
+ ret
+10:
+ movw SRC_LEN_0, r24
+ push_range 8, 11
+ movw DST_CTX_0, r30
/* 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+
rjmp 10b
11:
/* start of copy */
-
movw r24, SRC_LEN_0
12: /* copy loop */
std Z+1, TMP_1
movw r24, r30
99:
- pop_range 6, 11
+ pop_range 8, 11
rjmp bigint_adjust
40:
- /* TODO */
/* Z points at DST_WORDV */
/* X points at SRC_WORDV */
- /* r24:r25 contains scale - DST_LEN (negativ) */
+ /* r24:r25 and TMP contain scale - DST_LEN (negativ) */
/* set T bit if DST_LEN > SCR_LEN + scale */
clt
add r30, SCALE_0
+-------+-------+ SRC + scale
+------------+ DST
*/
- com r24 /* negate r24:r25 */
+ com r24 /* negate r24:r25 ==> DST_LEN - scale */
com r25
adiw r24, 1
+ breq 50f
44:
+ inc r25
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
+ dec r24
+ brne 46b
+ dec r25
+ brne 46b
-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
+50: ;st Z, r1
brtc 60f
51: brcc 53f
52: ld TMP_0, Z
st Z+, TMP_0
brcs 52b
53:
- /* TODO */
+ /* epilogue */
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
+ cp r24, DST_LEN_0
+ cpc r25, DST_LEN_1
+ brmi 54f
std Z+0, r24
std Z+1, r25
- movw r24, r30
+54: movw r24, r30
rjmp 99b
-60: rol r1 /* backup carry */
+60: st Z, r1
+ 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
+
+ adiw r24, 0
+ breq 63f
+ inc r25
ror r1 /* restore carry */
-61: dec r24
- brpl 62f
- dec r25
- brmi 63f
+61:
62: ld TMP_0, X+
adc TMP_0, r1
st Z+, TMP_0
- rjmp 61b
+ dec r24
+ brne 62b
+ dec r25
+ brne 62b
63:
brcc 53b
ldi r24, 1
projects / avr-crypto-lib.git / blobdiff