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OcGuardLib: Add U16 arithmetics

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This commit is contained in:
vit9696 2021-01-31 04:57:40 +03:00
parent 990ad449fe
commit 0d0279cc7f
2 changed files with 88 additions and 0 deletions
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21
Include/Acidanthera/Library/OcGuardLib.h
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@ -56,6 +56,27 @@ WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
// and multiplication with addition (A*B+C) support.
//
BOOLEAN
OcOverflowAddU16 (
UINT16 A,
UINT16 B,
UINT16 *Result
);
BOOLEAN
OcOverflowSubU16 (
UINT16 A,
UINT16 B,
UINT16 *Result
);
BOOLEAN
OcOverflowMulU16 (
UINT16 A,
UINT16 B,
UINT16 *Result
);
BOOLEAN
OcOverflowAddU32 (
UINT32 A,

67
Library/OcGuardLib/BitOverflow.c
View File

@ -26,6 +26,73 @@ WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
// target C99 compliance rather than performance.
//
BOOLEAN
OcOverflowAddU16 (
UINT16 A,
UINT16 B,
UINT16 *Result
)
{
#if defined(OC_HAS_TYPE_GENERIC_BUILTINS)
return __builtin_add_overflow(A, B, Result);
#else
UINT32 Temp;
//
// I believe casting will be faster on X86 at least.
//
Temp = A + B;
*Result = (UINT16) Temp;
if (Temp <= MAX_UINT16) {
return FALSE;
}
return TRUE;
#endif
}
BOOLEAN
OcOverflowSubU16 (
UINT16 A,
UINT16 B,
UINT16 *Result
)
{
#if defined(OC_HAS_TYPE_GENERIC_BUILTINS)
return __builtin_sub_overflow(A, B, Result);
#else
*Result = (UINT16) (A - B);
if (A >= B) {
return FALSE;
}
return TRUE;
#endif
}
BOOLEAN
OcOverflowMulU16 (
UINT16 A,
UINT16 B,
UINT16 *Result
)
{
#if defined(OC_HAS_TYPE_GENERIC_BUILTINS)
return __builtin_mul_overflow(A, B, Result);
#else
UINT32 Temp;
Temp = (UINT32) A * B;
*Result = (UINT16) Temp;
if (Temp <= MAX_UINT32) {
return FALSE;
}
return TRUE;
#endif
}
BOOLEAN
OcOverflowAddU32 (
UINT32 A,