big: Add Frobenius-Underwood.

1 files changed, 11 insertions, 1 deletions

diff --git a/core/math/big/internal.odin b/core/math/big/internal.odin
index c603dcdd8..6ae2f4284 100644
--- a/core/math/big/internal.odin
+++ b/core/math/big/internal.odin
@@ -2019,8 +2019,18 @@ internal_invmod :: proc{ internal_int_inverse_modulo, };
 /*
 	Helpers to extract values from the `Int`.
 */
+internal_int_bitfield_extract_bool :: proc(a: ^Int, offset: int) -> (val: bool, err: Error) {
+	limb := offset / _DIGIT_BITS;
+	if limb < 0 || limb >= a.used  { return false, .Invalid_Argument; }
+	i := _WORD(1 << _WORD((offset % _DIGIT_BITS)));
+	return bool(_WORD(a.digit[limb]) & i), nil;
+}
+
 internal_int_bitfield_extract_single :: proc(a: ^Int, offset: int) -> (bit: _WORD, err: Error) {
-	return #force_inline int_bitfield_extract(a, offset, 1);
+	limb := offset / _DIGIT_BITS;
+	if limb < 0 || limb >= a.used  { return 0, .Invalid_Argument; }
+	i := _WORD(1 << _WORD((offset % _DIGIT_BITS)));
+	return 1 if ((_WORD(a.digit[limb]) & i) != 0) else 0, nil;
 }
 
 internal_int_bitfield_extract :: proc(a: ^Int, offset, count: int) -> (res: _WORD, err: Error) #no_bounds_check {