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cbe: fix shl/shr

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- zig_shr_u128 was actually shifting left
- handle shifting by zero explicitly (shifting u64 by 64 is undefined behaviour)
This commit is contained in:
kcbanner 2022-12-16 21:41:52 -05:00
parent 2d34477dbb
commit b6f0af57a2
1 changed files with 7 additions and 4 deletions
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11
lib/zig.h
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@ -1327,17 +1327,20 @@ static inline zig_i128 zig_not_i128(zig_i128 val, zig_u8 bits) {
}
static inline zig_u128 zig_shr_u128(zig_u128 lhs, zig_u8 rhs) {
if (rhs >= zig_as_u8(64)) return (zig_u128){ .hi = lhs.hi << (rhs - zig_as_u8(64)), .lo = zig_minInt_u64 };
return (zig_u128){ .hi = lhs.hi << rhs | lhs.lo >> (zig_as_u8(64) - rhs), .lo = lhs.lo << rhs };
if (rhs == zig_as_u8(0)) return lhs;
if (rhs >= zig_as_u8(64)) return (zig_u128){ .hi = zig_minInt_u64, .lo = lhs.hi >> (rhs - zig_as_u8(64)) };
return (zig_u128){ .hi = lhs.hi >> rhs, .lo = lhs.hi << (zig_as_u8(64) - rhs) | lhs.lo >> rhs };
}
static inline zig_u128 zig_shl_u128(zig_u128 lhs, zig_u8 rhs) {
if (rhs >= zig_as_u8(64)) return (zig_u128){ .hi = lhs.hi << (rhs - zig_as_u8(64)), .lo = zig_minInt_u64 };
if (rhs == zig_as_u8(0)) return lhs;
if (rhs >= zig_as_u8(64)) return (zig_u128){ .hi = lhs.lo << rhs, .lo = zig_minInt_u64 };
return (zig_u128){ .hi = lhs.hi << rhs | lhs.lo >> (zig_as_u8(64) - rhs), .lo = lhs.lo << rhs };
}
static inline zig_i128 zig_shl_i128(zig_i128 lhs, zig_u8 rhs) {
if (rhs >= zig_as_u8(64)) return (zig_i128){ .hi = lhs.hi << (rhs - zig_as_u8(64)), .lo = zig_minInt_u64 };
if (rhs == zig_as_u8(0)) return lhs;
if (rhs >= zig_as_u8(64)) return (zig_i128){ .hi = lhs.hi << (rhs - zig_as_u8(64)), .lo = zig_minInt_u64 }; // TODO: Fix?
return (zig_i128){ .hi = lhs.hi << rhs | lhs.lo >> (zig_as_u8(64) - rhs), .lo = lhs.lo << rhs };
}