adding modulo-reduction to bigint

This commit is contained in:
bg 2010-03-04 18:34:50 +00:00
parent eb09a2a6f4
commit 4bd4efef59
4 changed files with 226 additions and 16 deletions

View File

@ -344,19 +344,18 @@ void bigint_shiftleft(bigint_t* a, uint16_t shift){
t >>= 8;
}
a->wordv[i] = (uint8_t)t;
byteshift++;
}else{ /* shift to the right */
bitshift = 8 - bitshift;
for(i=a->length_B+byteshift-1; i>byteshift; --i){
t |= (a->wordv[i])<<(8-bitshift);
for(i=a->length_B+byteshift-1; i>byteshift-1; --i){
t |= (a->wordv[i])<<(bitshift);
a->wordv[i] = (uint8_t)(t>>8);
t <<= 8;
}
t |= (a->wordv[i])<<(8-bitshift);
t |= (a->wordv[i])<<(bitshift);
a->wordv[i] = (uint8_t)(t>>8);
}
}
a->length_B += byteshift+1;
a->length_B += byteshift;
bigint_adjust(a);
}
@ -422,7 +421,6 @@ void bigint_set_zero(bigint_t* a){
void bigint_mul_u(bigint_t* dest, const bigint_t* a, const bigint_t* b){
if(a->length_B==0 || b->length_B==0){
bigint_set_zero(dest);
depth -= 1;
return;
}
if(a->length_B==1 || b->length_B==1){
@ -488,7 +486,6 @@ void bigint_mul_u(bigint_t* dest, const bigint_t* a, const bigint_t* b){
/* now we have split up a and b */
uint8_t tmp_b[2*n+2], m_b[2*(n+1)];
bigint_t tmp, tmp2, m;
/* calculate h=xh*yh; l=xl*yl; sx=xh+xl; sy=yh+yl */
tmp.wordv = tmp_b;
tmp2.wordv = tmp_b+n+1;
m.wordv = m_b;
@ -562,12 +559,70 @@ void bigint_square(bigint_t* dest, const bigint_t* a){
bigint_mul_u(&tmp, &xl, &xh);
bigint_shiftleft(&tmp, 1);
bigint_add_scale_u(dest, &tmp, n);
}
/******************************************************************************/
void bigint_sub_u_bitscale(bigint_t* a, const bigint_t* b, uint16_t bitscale){
bigint_t tmp;
uint8_t tmp_b[b->length_B+1];
uint16_t i,j,byteshift=bitscale/8;
uint8_t borrow=0;
int16_t t;
if(a->length_B < b->length_B+byteshift){
cli_putstr_P(PSTR("\r\nERROR: bigint_sub_u_bitscale result negative"));
bigint_set_zero(a);
return;
}
tmp.wordv = tmp_b;
bigint_copy(&tmp, b);
bigint_shiftleft(&tmp, bitscale&7);
for(j=0,i=byteshift; i<tmp.length_B+byteshift; ++i, ++j){
t = a->wordv[i] - tmp.wordv[j] - borrow;
a->wordv[i] = (uint8_t)t;
if(t<0){
borrow = 1;
}else{
borrow = 0;
}
}
while(borrow){
if(i+1 > a->length_B){
cli_putstr_P(PSTR("\r\nERROR: bigint_sub_u_bitscale result negative (2) shift="));
cli_hexdump_rev(&bitscale, 2);
bigint_set_zero(a);
return;
}
a->wordv[i] -= borrow;
if(a->wordv[i]!=0xff){
borrow=0;
}
++i;
}
bigint_adjust(a);
}
/******************************************************************************/
void bigint_reduce(bigint_t* a, const bigint_t* r){
uint8_t rfbs = GET_FBS(r);
if(r->length_B==0){
return;
}
while(a->length_B > r->length_B){
bigint_sub_u_bitscale(a, r, (a->length_B-r->length_B)*8+GET_FBS(a)-rfbs-1);
}
while(GET_FBS(a) > rfbs+1){
bigint_sub_u_bitscale(a, r, GET_FBS(a)-rfbs-1);
}
while(bigint_cmp_u(a,r)>=0){
bigint_sub_u(a,a,r);
}
bigint_adjust(a);
}

View File

@ -42,7 +42,7 @@ typedef struct{
/******************************************************************************/
void bigint_adjust(bigint_t* a);
void bigint_copy(bigint_t* dest, const bigint_t* src);
void bigint_copy(bigint_t* dest, const bigint_t* src);
void bigint_add_u(bigint_t* dest, const bigint_t* a, const bigint_t* b);
void bigint_add_scale_u(bigint_t* dest, const bigint_t* a, uint16_t scale);
void bigint_sub_u(bigint_t* dest, const bigint_t* a, const bigint_t* b);
@ -57,7 +57,8 @@ void bigint_set_zero(bigint_t* a);
void bigint_mul_u(bigint_t* dest, const bigint_t* a, const bigint_t* b);
void bigint_mul_s(bigint_t* dest, const bigint_t* a, const bigint_t* b);
void bigint_square(bigint_t* dest, const bigint_t* a);
void bigint_sub_u_bitscale(bigint_t* a, const bigint_t* b, uint16_t bitscale);
void bigint_reduce(bigint_t* a, const bigint_t* r);
/******************************************************************************/
#endif /*BIGINT_H_*/

View File

@ -234,6 +234,55 @@ def square_test(a)
return false
end
################################################################################
# reduce_test #
################################################################################
def reduce_test(a,b)
begin
line = $sp.gets()
line = "" if line==nil
puts("DBG got: "+line) if $debug
if /^Error:.*/.match(line)
puts line
return false
end
end while not /[\s]*enter a:[\s]*/.match(line)
$sp.print(a.to_s(16)+" ")
begin
line = $sp.gets()
line = "" if line==nil
puts("DBG got: "+line) if $debug
if /^Error:.*/.match(line)
puts line
return false
end
end while not /[\s]*enter b:[\s]*/.match(line)
$sp.print(b.to_s(16)+" ")
begin
line = $sp.gets()
line = "" if line==nil
puts("DBG got: "+line) if $debug
if /^Error:.*/.match(line)
puts line
return false
end
end while not m=/[\s]*([+-]?[0-9a-fA-F]*)[\s]+%[\s]+([+-]?[0-9a-fA-F]*)[\s]*=[\s]*([+-]?[0-9a-fA-F]*)/.match(line)
a_ = m[1].to_i(16)
b_ = m[2].to_i(16)
c_ = m[3].to_i(16)
line.chomp!
if(a_== a && b_ == b && c_ == (a%b))
$logfile.printf("[pass]: %s\n", line)
return true
else
$logfile.printf("[fail (%s%s%s)]: %s", (a==a_)?"":"a", (b==b_)?"":"b", (c_==a+b)?"":"c",line)
$logfile.printf(" ; should %s %% %s = %s\n", a.to_s(16), b.to_s(16), (a%b).to_s(16))
return false
end
return false
end
################################################################################
# run_test_add #
################################################################################
@ -322,6 +371,33 @@ def run_test_square(skip=0)
end while length_a_B<4096/8
end
################################################################################
# run_test_reduce #
################################################################################
def run_test_reduce(skip=0)
length_a_B = skip+1
length_b_B = skip+1
begin
$size = length_a_B
(0..16).each do |i|
a = rand(256**length_a_B)
b = rand(256**length_a_B)+1
v = reduce_test(a, b)
screen_progress(v)
end
(0..16).each do |i|
b_size = rand(length_b_B+1)
a = rand(256**length_a_B)
b = rand(256**b_size)+1
v = reduce_test(a, b)
screen_progress(v)
end
length_a_B += 1
length_b_B += 1
end while length_a_B<4096/8
end
################################################################################
# MAIN #
################################################################################
@ -395,10 +471,12 @@ tests = Hash.new
tests['a'] = proc {|x| run_test_add(x) }
tests['m'] = proc {|x| run_test_mul(x) }
tests['s'] = proc {|x| run_test_square(x) }
tests['r'] = proc {|x| run_test_reduce(x) }
init_str = Hash.new
init_str['a'] = 'add-test'
init_str['m'] = 'mul-test'
init_str['s'] = 'square-test'
init_str['r'] = 'reduce-test'
srand(0xdeadbeef)
@ -413,7 +491,7 @@ if opts['a']
end
end
else
'ams'.each_char do |x|
'amsr'.each_char do |x|
if tests[x]
puts init_str[x]
init_system(init_str[x])

View File

@ -163,6 +163,34 @@ void test_square_bigint(void){
}
}
void test_reduce_bigint(void){
bigint_t a, b, c;
cli_putstr_P(PSTR("\r\nreduce test\r\n"));
for(;;){
cli_putstr_P(PSTR("\r\nenter a:"));
if(bigint_read_hex_echo(&a)){
cli_putstr_P(PSTR("\r\n end reduce test"));
return;
}
cli_putstr_P(PSTR("\r\nenter b:"));
if(bigint_read_hex_echo(&b)){
free(a.wordv);
cli_putstr_P(PSTR("\r\n end reduce test"));
return;
}
cli_putstr_P(PSTR("\r\n "));
bigint_print_hex(&a);
cli_putstr_P(PSTR(" % "));
bigint_print_hex(&b);
cli_putstr_P(PSTR(" = "));
bigint_reduce(&a, &b);
bigint_print_hex(&a);
cli_putstr_P(PSTR("\r\n"));
free(a.wordv);
free(b.wordv);
}
}
void test_simple(void){
bigint_t a, b, c;
uint8_t a_b[1], b_b[1], c_b[2];
@ -226,6 +254,26 @@ void test_mul_simple(void){
}
// f4 b86a 2220 0774 437d 70e6 **2 = e9f00f29ca1c876a7a682bd1e04f6925caffd6660ea4
/*
uint8_t square_test_data[] PROGMEM = {
0xA0, 0x3C, 0x23, 0x9F, 0x7A, 0xFC, 0x60, 0xEB, 0x96, 0xC2, 0xA8, 0xAC, 0xC3, 0xC9, 0x9E, 0xEC,
0x4A, 0xF0, 0x1C, 0xB2, 0x36, 0x68, 0xD6, 0x4D, 0x3E, 0x4F, 0x8E, 0x55, 0xEA, 0x52, 0x46, 0x68,
0x6E, 0x18, 0x88, 0x37, 0x03, 0x70, 0xBD, 0x01, 0x60, 0xE2, 0xD6, 0x12, 0xA0, 0x0E, 0xD2, 0x72,
0x0D, 0x9D, 0x9F, 0x03, 0xC5, 0x81, 0xCA, 0x6E, 0x88, 0x1E, 0xF5, 0xD8, 0x14, 0x15, 0x30, 0xEB,
0x28, 0x7C, 0x80, 0x07, 0x34, 0x05, 0x5D, 0xAA, 0xDC, 0xA8, 0xAA, 0x88, 0xC5, 0xE5, 0xC9, 0xFE,
0x9C, 0xA1, 0xCE, 0xC2, 0x09, 0x0D, 0xC4, 0xC8, 0xD3, 0xE7, 0x3A, 0xF3, 0xEF, 0xDF, 0xAE, 0x07,
0xEC, 0xC7, 0x83, 0x50, 0x9F, 0x6D, 0xB9, 0x28, 0x77, 0xC0, 0xFE, 0x69, 0xB2, 0x2E, 0x55, 0x90,
0x50, 0xED, 0xE0, 0xA1, 0x4D, 0x3D, 0x38, 0xC9, 0x0E, 0xCD, 0x04, 0x3B, 0x64, 0x3F, 0x56, 0xC5,
0xC3, 0x9E, 0x89, 0x81, 0x44, 0x60, 0xBA, 0x8E, 0x88, 0xA4, 0xA3, 0x42, 0x7B, 0x06, 0x93, 0x1C,
0x6B, 0x04, 0x29, 0xF9, 0xDD, 0xFF, 0xB0, 0x48, 0x2F, 0x6D, 0xD1, 0x0F, 0x7D, 0xA6, 0x26, 0xD8,
0xEF, 0x5E, 0x04, 0x18, 0xD1, 0x61, 0x46, 0x37, 0x87, 0xE2, 0x97, 0xDF, 0x10, 0xB4, 0x9A, 0x39,
0xB1, 0xD0, 0xCA, 0x91, 0x48, 0x1E, 0x5D, 0xA1, 0x38, 0x89, 0x02, 0xC1, 0x49, 0x86, 0xB7, 0xAE,
0x69, 0x20, 0xFA, 0x0E, 0x39, 0xDA, 0xA5, 0xEF, 0x7F, 0xB2, 0x81, 0xB8, 0xC0, 0x3A, 0xF8, 0xDB,
0xBC, 0x45, 0xF6, 0xDA, 0xCD, 0xBE, 0x27, 0xBE, 0xF6, 0x20, 0x79, 0xF3, 0xC3, 0xC8, 0xFF, 0x85,
0x43, 0x9F, 0xB1, 0x9B, 0x72, 0x88, 0xDD, 0xA4, 0x0D, 0xFC, 0xC6, 0xB5, 0x74, 0x67, 0x29, 0xF5
};
*/
void test_square_simple(void){
bigint_t a, c;
@ -243,6 +291,32 @@ void test_square_simple(void){
bigint_print_hex(&c);
}
// [fail (c)]: A862 % 2752 = 0D1A ; should a862 % 2752 = b1a
void test_reduce_simple(void){
bigint_t a, b, c;
uint8_t a_b[2] = {0x62, 0xA8};
uint8_t b_b[2] = {0x52, 0x27};
uint8_t c_b[2];
a.wordv=a_b;
a.length_B = 2;
a.info=0x00;
bigint_adjust(&a);
b.wordv=b_b;
b.length_B = 2;
b.info=0x00;
bigint_adjust(&b);
c.wordv = c_b;
bigint_copy(&c, &a);
bigint_reduce(&c, &b);
cli_putstr_P(PSTR("\r\n test: "));
bigint_print_hex(&a);
cli_putstr_P(PSTR(" % "));
bigint_print_hex(&b);
cli_putstr_P(PSTR(" = "));
bigint_print_hex(&c);
}
void testrun_performance_bigint(void){
@ -255,6 +329,7 @@ const char echo_test_str[] PROGMEM = "echo-test";
const char add_test_str[] PROGMEM = "add-test";
const char mul_test_str[] PROGMEM = "mul-test";
const char square_test_str[] PROGMEM = "square-test";
const char reduce_test_str[] PROGMEM = "reduce-test";
const char quick_test_str[] PROGMEM = "quick-test";
const char performance_str[] PROGMEM = "performance";
const char echo_str[] PROGMEM = "echo";
@ -263,7 +338,8 @@ cmdlist_entry_t cmdlist[] PROGMEM = {
{ add_test_str, NULL, test_add_bigint },
{ mul_test_str, NULL, test_mul_bigint },
{ square_test_str, NULL, test_square_bigint },
{ quick_test_str, NULL, test_mul_simple },
{ reduce_test_str, NULL, test_reduce_bigint },
{ quick_test_str, NULL, test_reduce_simple },
{ echo_test_str, NULL, test_echo_bigint },
{ performance_str, NULL, testrun_performance_bigint },
{ echo_str, (void*)1, (void_fpt)echo_ctrl },