Add math.pow2_f{16,32,64}, fast floating point 2^x where x is an integer.

This commit is contained in:
Jeroen van Rijn
2023-11-04 22:14:44 +01:00
parent 5edb2c5688
commit 6201280468
4 changed files with 122 additions and 4 deletions

View File

@@ -203,7 +203,54 @@ pow10_f64 :: proc "contextless" (n: f64) -> f64 {
return 0
}
pow2_f64 :: proc(#any_int exp: int) -> (res: f64) {
switch {
case exp >= -1022 && exp <= 1023: // Normal
return transmute(f64)(u64(exp + F64_BIAS) << F64_SHIFT)
case exp < -1075: // Underflow
return f64(0)
case exp == -1075: // Underflow
return 0h00000000_00000001
case exp < -1022: // Denormal
x := u64(exp + (F64_SHIFT + 1) + F64_BIAS) << F64_SHIFT
return f64(1) / (1 << (F64_SHIFT + 1)) * transmute(f64)x
case exp > 1023: // Overflow, +Inf
return 0h7ff00000_00000000
}
unreachable()
}
pow2_f32 :: proc(#any_int exp: int) -> (res: f32) {
switch {
case exp >= -126 && exp <= 127: // Normal
return transmute(f32)(u32(exp + F32_BIAS) << F32_SHIFT)
case exp < -151: // Underflow
return f32(0)
case exp < -126: // Denormal
x := u32(exp + (F32_SHIFT + 1) + F32_BIAS) << F32_SHIFT
return f32(1) / (1 << (F32_SHIFT + 1)) * transmute(f32)x
case exp > 127: // Overflow, +Inf
return 0h7f80_0000
}
unreachable()
}
pow2_f16 :: proc(#any_int exp: int) -> (res: f16) {
switch {
case exp >= -14 && exp <= 15: // Normal
return transmute(f16)(u16(exp + F16_BIAS) << F16_SHIFT)
case exp < -25: // Underflow
return 0h0000
case exp == -25: // Underflow
return 0h0001
case exp < -14: // Denormal
x := u16(exp + (F16_SHIFT + 1) + F16_BIAS) << F16_SHIFT
return f16(1) / (1 << (F16_SHIFT + 1)) * transmute(f16)x
case exp > 15: // Overflow, +Inf
return 0h7c00
}
unreachable()
}
@(require_results)
ldexp_f64 :: proc "contextless" (val: f64, exp: int) -> f64 {
@@ -2302,4 +2349,4 @@ INF_F64 :: f64(0h7FF0_0000_0000_0000)
NEG_INF_F64 :: f64(0hFFF0_0000_0000_0000)
SNAN_F64 :: f64(0h7FF0_0000_0000_0001)
QNAN_F64 :: f64(0h7FF8_0000_0000_0001)
QNAN_F64 :: f64(0h7FF8_0000_0000_0001)

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@@ -1,9 +1,12 @@
ODIN=../../odin
all: rtti_test map_test
all: rtti_test map_test pow_test
rtti_test:
$(ODIN) run test_rtti.odin -file -vet -strict-style -o:minimal
map_test:
$(ODIN) run test_map.odin -file -vet -strict-style -o:minimal
$(ODIN) run test_map.odin -file -vet -strict-style -o:minimal
pow_test:
$(ODIN) run test_pow.odin -file -vet -strict-style -o:minimal

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@@ -2,4 +2,5 @@
set PATH_TO_ODIN==..\..\odin
rem %PATH_TO_ODIN% run test_rtti.odin -file -vet -strict-style -o:minimal || exit /b
%PATH_TO_ODIN% run test_map.odin -file -vet -strict-style -o:minimal || exit /b
rem -define:SEED=42
rem -define:SEED=42
%PATH_TO_ODIN% run test_pow.odin -file -vet -strict-style -o:minimal || exit /b

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@@ -0,0 +1,67 @@
package test_internal_math_pow
import "core:fmt"
import "core:math"
import "core:os"
import "core:testing"
@test
pow_test :: proc(t: ^testing.T) {
for exp in -2000..=2000 {
{
v1 := math.pow(2, f64(exp))
v2 := math.pow2_f64(exp)
_v1 := transmute(u64)v1
_v2 := transmute(u64)v2
expect(t, _v1 == _v2, fmt.tprintf("Expected math.pow2_f64(%d) == math.pow(2, %d) (= %x), got %x", exp, exp, v1, v2))
}
{
v1 := math.pow(2, f32(exp))
v2 := math.pow2_f32(exp)
_v1 := transmute(u32)v1
_v2 := transmute(u32)v2
expect(t, _v1 == _v2, fmt.tprintf("Expected math.pow2_f32(%d) == math.pow(2, %d) (= %x), got %x", exp, exp, v1, v2))
}
{
v1 := math.pow(2, f16(exp))
v2 := math.pow2_f16(exp)
_v1 := transmute(u16)v1
_v2 := transmute(u16)v2
expect(t, _v1 == _v2, fmt.tprintf("Expected math.pow2_f16(%d) == math.pow(2, %d) (= %x), got %x", exp, exp, v1, v2))
}
}
}
// -------- -------- -------- -------- -------- -------- -------- -------- -------- --------
main :: proc() {
t := testing.T{}
pow_test(&t)
fmt.printf("%v/%v tests successful.\n", TEST_count - TEST_fail, TEST_count)
if TEST_fail > 0 {
os.exit(1)
}
}
TEST_count := 0
TEST_fail := 0
when ODIN_TEST {
expect :: testing.expect
log :: testing.log
} else {
expect :: proc(t: ^testing.T, condition: bool, message: string, loc := #caller_location) {
TEST_count += 1
if !condition {
TEST_fail += 1
fmt.printf("[%v] %v\n", loc, message)
return
}
}
log :: proc(t: ^testing.T, v: any, loc := #caller_location) {
fmt.printf("[%v] ", loc)
fmt.printf("log: %v\n", v)
}
}