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strconv,math.bits: eliminate bounds checking in commonly used routines

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Delyan Angelov 2024-07-22 13:43:50 +03:00
parent 9179038e86
commit d9a3a3aa0a
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GPG Key ID: 66886C0F12D595ED
2 changed files with 17 additions and 2 deletions
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15
vlib/math/bits/bits.v
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@ -45,11 +45,13 @@ pub fn leading_zeros_64(x u64) int {
// --- TrailingZeros --- // --- TrailingZeros ---
// trailing_zeros_8 returns the number of trailing zero bits in x; the result is 8 for x == 0. // trailing_zeros_8 returns the number of trailing zero bits in x; the result is 8 for x == 0.
@[direct_array_access]
pub fn trailing_zeros_8(x u8) int { pub fn trailing_zeros_8(x u8) int {
return int(ntz_8_tab[x]) return int(ntz_8_tab[x])
} }
// trailing_zeros_16 returns the number of trailing zero bits in x; the result is 16 for x == 0. // trailing_zeros_16 returns the number of trailing zero bits in x; the result is 16 for x == 0.
@[direct_array_access]
pub fn trailing_zeros_16(x u16) int { pub fn trailing_zeros_16(x u16) int {
if x == 0 { if x == 0 {
return 16 return 16
@ -59,6 +61,7 @@ pub fn trailing_zeros_16(x u16) int {
} }
// trailing_zeros_32 returns the number of trailing zero bits in x; the result is 32 for x == 0. // trailing_zeros_32 returns the number of trailing zero bits in x; the result is 32 for x == 0.
@[direct_array_access]
pub fn trailing_zeros_32(x u32) int { pub fn trailing_zeros_32(x u32) int {
if x == 0 { if x == 0 {
return 32 return 32
@ -68,6 +71,7 @@ pub fn trailing_zeros_32(x u32) int {
} }
// trailing_zeros_64 returns the number of trailing zero bits in x; the result is 64 for x == 0. // trailing_zeros_64 returns the number of trailing zero bits in x; the result is 64 for x == 0.
@[direct_array_access]
pub fn trailing_zeros_64(x u64) int { pub fn trailing_zeros_64(x u64) int {
if x == 0 { if x == 0 {
return 64 return 64
@ -88,16 +92,19 @@ pub fn trailing_zeros_64(x u64) int {
// --- OnesCount --- // --- OnesCount ---
// ones_count_8 returns the number of one bits ("population count") in x. // ones_count_8 returns the number of one bits ("population count") in x.
@[direct_array_access]
pub fn ones_count_8(x u8) int { pub fn ones_count_8(x u8) int {
return int(pop_8_tab[x]) return int(pop_8_tab[x])
} }
// ones_count_16 returns the number of one bits ("population count") in x. // ones_count_16 returns the number of one bits ("population count") in x.
@[direct_array_access]
pub fn ones_count_16(x u16) int { pub fn ones_count_16(x u16) int {
return int(pop_8_tab[x >> 8] + pop_8_tab[x & u16(0xff)]) return int(pop_8_tab[x >> 8] + pop_8_tab[x & u16(0xff)])
} }
// ones_count_32 returns the number of one bits ("population count") in x. // ones_count_32 returns the number of one bits ("population count") in x.
@[direct_array_access]
pub fn ones_count_32(x u32) int { pub fn ones_count_32(x u32) int {
return int(pop_8_tab[x >> 24] + pop_8_tab[x >> 16 & 0xff] + pop_8_tab[x >> 8 & 0xff] + return int(pop_8_tab[x >> 24] + pop_8_tab[x >> 16 & 0xff] + pop_8_tab[x >> 8 & 0xff] +
pop_8_tab[x & u32(0xff)]) pop_8_tab[x & u32(0xff)])
@ -181,13 +188,13 @@ pub fn rotate_left_64(x u64, k int) u64 {
// --- Reverse --- // --- Reverse ---
// reverse_8 returns the value of x with its bits in reversed order. // reverse_8 returns the value of x with its bits in reversed order.
@[inline] @[direct_array_access; inline]
pub fn reverse_8(x u8) u8 { pub fn reverse_8(x u8) u8 {
return rev_8_tab[x] return rev_8_tab[x]
} }
// reverse_16 returns the value of x with its bits in reversed order. // reverse_16 returns the value of x with its bits in reversed order.
@[inline] @[direct_array_access; inline]
pub fn reverse_16(x u16) u16 { pub fn reverse_16(x u16) u16 {
return u16(rev_8_tab[x >> 8]) | (u16(rev_8_tab[x & u16(0xff)]) << 8) return u16(rev_8_tab[x >> 8]) | (u16(rev_8_tab[x & u16(0xff)]) << 8)
} }
@ -240,11 +247,13 @@ pub fn reverse_bytes_64(x u64) u64 {
// --- Len --- // --- Len ---
// len_8 returns the minimum number of bits required to represent x; the result is 0 for x == 0. // len_8 returns the minimum number of bits required to represent x; the result is 0 for x == 0.
@[direct_array_access]
pub fn len_8(x u8) int { pub fn len_8(x u8) int {
return int(len_8_tab[x]) return int(len_8_tab[x])
} }
// len_16 returns the minimum number of bits required to represent x; the result is 0 for x == 0. // len_16 returns the minimum number of bits required to represent x; the result is 0 for x == 0.
@[direct_array_access]
pub fn len_16(x u16) int { pub fn len_16(x u16) int {
mut y := x mut y := x
mut n := 0 mut n := 0
@ -256,6 +265,7 @@ pub fn len_16(x u16) int {
} }
// len_32 returns the minimum number of bits required to represent x; the result is 0 for x == 0. // len_32 returns the minimum number of bits required to represent x; the result is 0 for x == 0.
@[direct_array_access]
pub fn len_32(x u32) int { pub fn len_32(x u32) int {
mut y := x mut y := x
mut n := 0 mut n := 0
@ -271,6 +281,7 @@ pub fn len_32(x u32) int {
} }
// len_64 returns the minimum number of bits required to represent x; the result is 0 for x == 0. // len_64 returns the minimum number of bits required to represent x; the result is 0 for x == 0.
@[direct_array_access]
pub fn len_64(x u64) int { pub fn len_64(x u64) int {
mut y := x mut y := x
mut n := 0 mut n := 0

4
vlib/strconv/utilities.v
View File

@ -67,11 +67,15 @@ fn mul_shift_32(m u32, mul u64, ishift int) u32 {
return u32(shifted_sum) return u32(shifted_sum)
} }
@[direct_array_access; inline]
fn mul_pow5_invdiv_pow2(m u32, q u32, j int) u32 { fn mul_pow5_invdiv_pow2(m u32, q u32, j int) u32 {
assert1(q < pow5_inv_split_32.len, 'q < pow5_inv_split_32.len')
return mul_shift_32(m, pow5_inv_split_32[q], j) return mul_shift_32(m, pow5_inv_split_32[q], j)
} }
@[direct_array_access; inline]
fn mul_pow5_div_pow2(m u32, i u32, j int) u32 { fn mul_pow5_div_pow2(m u32, i u32, j int) u32 {
assert1(i < pow5_split_32.len, 'i < pow5_split_32.len')
return mul_shift_32(m, pow5_split_32[i], j) return mul_shift_32(m, pow5_split_32[i], j)
} }