Curle
4300dc655c
The lib/inc folders are from the GNU-EFI project. The documentation is from the uefi.org site. Yes, I know there are duplicate includes. I have a plan for them.
182 lines
3.4 KiB
C
182 lines
3.4 KiB
C
/*++
|
|
|
|
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
|
|
{
|
|
#if defined(__GNUC__) || defined(_MSC_EXTENSIONS)
|
|
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
|
|
{
|
|
#if defined(__GNUC__) || defined(_MSC_EXTENSIONS)
|
|
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
|
|
{
|
|
#if defined(__GNUC__) || defined(_MSC_EXTENSIONS)
|
|
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!!
|
|
{
|
|
#if defined(__GNUC__) || defined(_MSC_EXTENSIONS)
|
|
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
|
|
}
|