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dyncom: Add a helper function for addition with a carry

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This commit is contained in:
Lioncash 2015-01-12 00:01:46 -05:00
parent eacc2a501b
commit 9c2c89b7e1
3 changed files with 26 additions and 12 deletions
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16
src/core/arm/interpreter/armsupp.cpp
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@ -418,6 +418,22 @@ ARMul_NegZero (ARMul_State * state, ARMword result)
}
}
// Add with carry, indicates if a carry-out or signed overflow occurred.
u32 AddWithCarry(u32 left, u32 right, u32 carry_in, bool* carry_out_occurred, bool* overflow_occurred)
{
u64 unsigned_sum = (u64)left + (u64)right + (u64)carry_in;
s64 signed_sum = (s64)(s32)left + (s64)(s32)right + (s64)carry_in;
u64 result = (unsigned_sum & 0xFFFFFFFF);
if (carry_out_occurred)
*carry_out_occurred = (result != unsigned_sum);
if (overflow_occurred)
*overflow_occurred = ((s64)(s32)result != signed_sum);
return (u32)result;
}
// Compute whether an addition of A and B, giving RESULT, overflowed.
bool AddOverflow(ARMword a, ARMword b, ARMword result)
{