mirror of
https://github.com/CloverHackyColor/CloverBootloader.git
synced 2024-11-24 11:45:27 +01:00
89 lines
3.1 KiB
NASM
89 lines
3.1 KiB
NASM
;------------------------------------------------------------------------------
|
|
;
|
|
; Copyright (c) 2006, Intel Corporation. All rights reserved.<BR>
|
|
; SPDX-License-Identifier: BSD-2-Clause-Patent
|
|
;
|
|
; Module Name:
|
|
;
|
|
; DivU64x64Remainder.nasm
|
|
;
|
|
; Abstract:
|
|
;
|
|
; Calculate the quotient of a 64-bit integer by a 64-bit integer and returns
|
|
; both the quotient and the remainder
|
|
;
|
|
;------------------------------------------------------------------------------
|
|
|
|
SECTION .text
|
|
|
|
extern ASM_PFX(InternalMathDivRemU64x32)
|
|
|
|
;------------------------------------------------------------------------------
|
|
; UINT64
|
|
; EFIAPI
|
|
; InternalMathDivRemU64x64 (
|
|
; IN UINT64 Dividend,
|
|
; IN UINT64 Divisor,
|
|
; OUT UINT64 *Remainder OPTIONAL
|
|
; );
|
|
;------------------------------------------------------------------------------
|
|
global ASM_PFX(InternalMathDivRemU64x64)
|
|
ASM_PFX(InternalMathDivRemU64x64):
|
|
mov ecx, [esp + 16] ; ecx <- divisor[32..63]
|
|
test ecx, ecx
|
|
jnz _@DivRemU64x64 ; call _@DivRemU64x64 if Divisor > 2^32
|
|
mov ecx, [esp + 20]
|
|
jecxz .0
|
|
and dword [ecx + 4], 0 ; zero high dword of remainder
|
|
mov [esp + 16], ecx ; set up stack frame to match DivRemU64x32
|
|
.0:
|
|
jmp ASM_PFX(InternalMathDivRemU64x32)
|
|
|
|
_@DivRemU64x64:
|
|
push ebx
|
|
push esi
|
|
push edi
|
|
mov edx, dword [esp + 20]
|
|
mov eax, dword [esp + 16] ; edx:eax <- dividend
|
|
mov edi, edx
|
|
mov esi, eax ; edi:esi <- dividend
|
|
mov ebx, dword [esp + 24] ; ecx:ebx <- divisor
|
|
.1:
|
|
shr edx, 1
|
|
rcr eax, 1
|
|
shrd ebx, ecx, 1
|
|
shr ecx, 1
|
|
jnz .1
|
|
div ebx
|
|
mov ebx, eax ; ebx <- quotient
|
|
mov ecx, [esp + 28] ; ecx <- high dword of divisor
|
|
mul dword [esp + 24] ; edx:eax <- quotient * divisor[0..31]
|
|
imul ecx, ebx ; ecx <- quotient * divisor[32..63]
|
|
add edx, ecx ; edx <- (quotient * divisor)[32..63]
|
|
mov ecx, dword [esp + 32] ; ecx <- addr for Remainder
|
|
jc @TooLarge ; product > 2^64
|
|
cmp edi, edx ; compare high 32 bits
|
|
ja @Correct
|
|
jb @TooLarge ; product > dividend
|
|
cmp esi, eax
|
|
jae @Correct ; product <= dividend
|
|
@TooLarge:
|
|
dec ebx ; adjust quotient by -1
|
|
jecxz @Return ; return if Remainder == NULL
|
|
sub eax, dword [esp + 24]
|
|
sbb edx, dword [esp + 28] ; edx:eax <- (quotient - 1) * divisor
|
|
@Correct:
|
|
jecxz @Return
|
|
sub esi, eax
|
|
sbb edi, edx ; edi:esi <- remainder
|
|
mov [ecx], esi
|
|
mov [ecx + 4], edi
|
|
@Return:
|
|
mov eax, ebx ; eax <- quotient
|
|
xor edx, edx ; quotient is 32 bits long
|
|
pop edi
|
|
pop esi
|
|
pop ebx
|
|
ret
|
|
|