mirror of https://github.com/acidanthera/audk.git
90 lines
3.8 KiB
ArmAsm
90 lines
3.8 KiB
ArmAsm
#------------------------------------------------------------------------------
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#
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# Copyright (c) 2006 - 2008, Intel Corporation. All rights reserved.<BR>
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# This program and the accompanying materials
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# are licensed and made available under the terms and conditions of the BSD License
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# which accompanies this distribution. The full text of the license may be found at
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# http://opensource.org/licenses/bsd-license.php.
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#
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# THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
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# WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
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#
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# Module Name:
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#
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# DivU64x64Remainder.S
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#
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# Abstract:
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#
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# Calculate the quotient of a 64-bit integer by a 64-bit integer and returns
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# both the quotient and the remainder
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#
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#------------------------------------------------------------------------------
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ASM_GLOBAL ASM_PFX(InternalMathDivRemU64x32), ASM_PFX(InternalMathDivRemU64x64)
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#------------------------------------------------------------------------------
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# UINT64
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# EFIAPI
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# InternalMathDivRemU64x64 (
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# IN UINT64 Dividend,
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# IN UINT64 Divisor,
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# OUT UINT64 *Remainder OPTIONAL
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# );
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#------------------------------------------------------------------------------
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ASM_PFX(InternalMathDivRemU64x64):
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movl 16(%esp), %ecx # ecx <- divisor[32..63]
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testl %ecx, %ecx
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jnz Hard # call _@DivRemU64x64 if Divisor > 2^32
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movl 20(%esp), %ecx
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jecxz L1
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and $0, 4(%ecx) # zero high dword of remainder
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movl %ecx, 16(%esp) # set up stack frame to match DivRemU64x32
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L1:
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jmp ASM_PFX(InternalMathDivRemU64x32)
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Hard:
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push %ebx
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push %esi
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push %edi
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mov 20(%esp), %edx
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mov 16(%esp), %eax # edx:eax <- dividend
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movl %edx, %edi
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movl %eax, %esi # edi:esi <- dividend
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mov 24(%esp), %ebx # ecx:ebx <- divisor
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L2:
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shrl %edx
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rcrl $1, %eax
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shrdl $1, %ecx, %ebx
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shrl %ecx
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jnz L2
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divl %ebx
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movl %eax, %ebx # ebx <- quotient
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movl 28(%esp), %ecx # ecx <- high dword of divisor
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mull 24(%esp) # edx:eax <- quotient * divisor[0..31]
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imull %ebx, %ecx # ecx <- quotient * divisor[32..63]
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addl %ecx, %edx # edx <- (quotient * divisor)[32..63]
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mov 32(%esp), %ecx # ecx <- addr for Remainder
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jc TooLarge # product > 2^64
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cmpl %edx, %edi # compare high 32 bits
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ja Correct
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jb TooLarge # product > dividend
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cmpl %eax, %esi
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jae Correct # product <= dividend
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TooLarge:
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decl %ebx # adjust quotient by -1
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jecxz Return # return if Remainder == NULL
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sub 24(%esp), %eax
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sbb 28(%esp), %edx # edx:eax <- (quotient - 1) * divisor
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Correct:
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jecxz Return
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subl %eax, %esi
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sbbl %edx, %edi # edi:esi <- remainder
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movl %esi, (%ecx)
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movl %edi, 4(%ecx)
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Return:
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movl %ebx, %eax # eax <- quotient
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xorl %edx, %edx # quotient is 32 bits long
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pop %edi
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pop %esi
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pop %ebx
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ret
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