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Simplifing mul_u32 and add carry

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This commit is contained in:
Tomasz Drwięga 2016-03-07 17:09:19 +01:00
parent cc0adf5442
commit e7be3c5378
1 changed files with 8 additions and 8 deletions
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16
util/bigint/src/uint.rs
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@ -73,17 +73,17 @@ macro_rules! uint_overflowing_add_reg {
let $name(ref you) = $other; let $name(ref you) = $other;
let mut ret = [0u64; $n_words]; let mut ret = [0u64; $n_words];
let mut carry = [0u64; $n_words + 1]; let mut carry = 0u64;
for i in 0..$n_words { for i in 0..$n_words {
let (res1, overflow1) = me[i].overflowing_add(you[i]); let (res1, overflow1) = me[i].overflowing_add(you[i]);
let (res2, overflow2) = res1.overflowing_add(carry[i]); let (res2, overflow2) = res1.overflowing_add(carry);
ret[i] = res2; ret[i] = res2;
carry[i+1] = overflow1 as u64 + overflow2 as u64; carry = overflow1 as u64 + overflow2 as u64;
} }
($name(ret), carry[$n_words] > 0) ($name(ret), carry > 0)
}) })
} }
@ -684,21 +684,21 @@ macro_rules! construct_uint {
fn overflowing_mul_u32(self, other: u32) -> (Self, bool) { fn overflowing_mul_u32(self, other: u32) -> (Self, bool) {
let $name(ref arr) = self; let $name(ref arr) = self;
let o = other as u64; let o = other as u64;
let mut carry = [0u64; $n_words + 1];
let mut ret = [0u64; $n_words]; let mut ret = [0u64; $n_words];
let mut carry = 0;
for i in 0..$n_words { for i in 0..$n_words {
let upper = o * (arr[i] >> 32); let upper = o * (arr[i] >> 32);
let lower = o * (arr[i] & 0xFFFFFFFF); let lower = o * (arr[i] & 0xFFFFFFFF);
let (res1, overflow1) = lower.overflowing_add(upper << 32); let (res1, overflow1) = lower.overflowing_add(upper << 32);
let (res2, overflow2) = res1.overflowing_add(carry[i]); let (res2, overflow2) = res1.overflowing_add(carry);
ret[i] = res2; ret[i] = res2;
carry[i + 1] = (upper >> 32) + overflow1 as u64 + overflow2 as u64; carry = (upper >> 32) + overflow1 as u64 + overflow2 as u64;
} }
($name(ret), carry[$n_words] > 0) ($name(ret), carry > 0)
} }
} }