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/*++
Copyright (c) 1998 Intel Corporation
Module Name:
math.c
Abstract:
Revision History
--*/
#include "lib.h"
//
// Declare runtime functions
//
#ifdef RUNTIME_CODE
#ifndef __GNUC__
#pragma RUNTIME_CODE(LShiftU64)
#pragma RUNTIME_CODE(RShiftU64)
#pragma RUNTIME_CODE(MultU64x32)
#pragma RUNTIME_CODE(DivU64x32)
#endif
#endif
//
//
//
UINT64
LShiftU64 (
IN UINT64 Operand,
IN UINTN Count
)
// Left shift 64bit by 32bit and get a 64bit result
{
#ifdef __GNUC__
return Operand << Count;
#else
UINT64 Result;
_asm {
mov eax, dword ptr Operand[0]
mov edx, dword ptr Operand[4]
mov ecx, Count
and ecx, 63
shld edx, eax, cl
shl eax, cl
cmp ecx, 32
jc short ls10
mov edx, eax
xor eax, eax
ls10:
mov dword ptr Result[0], eax
mov dword ptr Result[4], edx
}
return Result;
#endif
}
UINT64
RShiftU64 (
IN UINT64 Operand,
IN UINTN Count
)
// Right shift 64bit by 32bit and get a 64bit result
{
#ifdef __GNUC__
return Operand >> Count;
#else
UINT64 Result;
_asm {
mov eax, dword ptr Operand[0]
mov edx, dword ptr Operand[4]
mov ecx, Count
and ecx, 63
shrd eax, edx, cl
shr edx, cl
cmp ecx, 32
jc short rs10
mov eax, edx
xor edx, edx
rs10:
mov dword ptr Result[0], eax
mov dword ptr Result[4], edx
}
return Result;
#endif
}
UINT64
MultU64x32 (
IN UINT64 Multiplicand,
IN UINTN Multiplier
)
// Multiple 64bit by 32bit and get a 64bit result
{
#ifdef __GNUC__
return Multiplicand * Multiplier;
#else
UINT64 Result;
_asm {
mov eax, dword ptr Multiplicand[0]
mul Multiplier
mov dword ptr Result[0], eax
mov dword ptr Result[4], edx
mov eax, dword ptr Multiplicand[4]
mul Multiplier
add dword ptr Result[4], eax
}
return Result;
#endif
}
UINT64
DivU64x32 (
IN UINT64 Dividend,
IN UINTN Divisor,
OUT UINTN *Remainder OPTIONAL
)
// divide 64bit by 32bit and get a 64bit result
// N.B. only works for 31bit divisors!!
{
#ifdef __GNUC__
if (Remainder)
*Remainder = Dividend % Divisor;
return Dividend / Divisor;
#else
UINT32 Rem;
UINT32 bit;
ASSERT (Divisor != 0);
ASSERT ((Divisor >> 31) == 0);
//
// For each bit in the dividend
//
Rem = 0;
for (bit=0; bit < 64; bit++) {
_asm {
shl dword ptr Dividend[0], 1 ; shift rem:dividend left one
rcl dword ptr Dividend[4], 1
rcl dword ptr Rem, 1
mov eax, Rem
cmp eax, Divisor ; Is Rem >= Divisor?
cmc ; No - do nothing
sbb eax, eax ; Else,
sub dword ptr Dividend[0], eax ; set low bit in dividen
and eax, Divisor ; and
sub Rem, eax ; subtract divisor
}
}
if (Remainder) {
*Remainder = Rem;
}
return Dividend;
#endif
}
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