projects / mirror_edk2.git / blame
| Commit | Line | Data |
|---|---|---|
| 6074ca70 JJ |
1 | ;------------------------------------------------------------------------------\r |
| 2 | ;\r | |
| 3 | ; Copyright (c) 2006, Intel Corporation. All rights reserved.<BR>\r | |
| 9344f092 | 4 | ; SPDX-License-Identifier: BSD-2-Clause-Patent\r |
| 6074ca70 JJ |
5 | ;\r |
| 6 | ; Module Name:\r | |
| 7 | ;\r | |
| 8 | ; DivU64x64Remainder.nasm\r | |
| 9 | ;\r | |
| 10 | ; Abstract:\r | |
| 11 | ;\r | |
| 12 | ; Calculate the quotient of a 64-bit integer by a 64-bit integer and returns\r | |
| 13 | ; both the quotient and the remainder\r | |
| 14 | ;\r | |
| 15 | ;------------------------------------------------------------------------------\r | |
| 16 | \r | |
| 17 | SECTION .text\r | |
| 18 | \r | |
| 19 | extern ASM_PFX(InternalMathDivRemU64x32)\r | |
| 20 | \r | |
| 21 | ;------------------------------------------------------------------------------\r | |
| 22 | ; UINT64\r | |
| 23 | ; EFIAPI\r | |
| 24 | ; InternalMathDivRemU64x64 (\r | |
| 25 | ; IN UINT64 Dividend,\r | |
| 26 | ; IN UINT64 Divisor,\r | |
| 27 | ; OUT UINT64 *Remainder OPTIONAL\r | |
| 28 | ; );\r | |
| 29 | ;------------------------------------------------------------------------------\r | |
| 30 | global ASM_PFX(InternalMathDivRemU64x64)\r | |
| 31 | ASM_PFX(InternalMathDivRemU64x64):\r | |
| 32 | mov ecx, [esp + 16] ; ecx <- divisor[32..63]\r | |
| 33 | test ecx, ecx\r | |
| 34 | jnz _@DivRemU64x64 ; call _@DivRemU64x64 if Divisor > 2^32\r | |
| 35 | mov ecx, [esp + 20]\r | |
| 36 | jecxz .0\r | |
| 37 | and dword [ecx + 4], 0 ; zero high dword of remainder\r | |
| 38 | mov [esp + 16], ecx ; set up stack frame to match DivRemU64x32\r | |
| 39 | .0:\r | |
| 40 | jmp ASM_PFX(InternalMathDivRemU64x32)\r | |
| 41 | \r | |
| 42 | _@DivRemU64x64:\r | |
| 43 | push ebx\r | |
| 44 | push esi\r | |
| 45 | push edi\r | |
| 46 | mov edx, dword [esp + 20]\r | |
| 47 | mov eax, dword [esp + 16] ; edx:eax <- dividend\r | |
| 48 | mov edi, edx\r | |
| 49 | mov esi, eax ; edi:esi <- dividend\r | |
| 50 | mov ebx, dword [esp + 24] ; ecx:ebx <- divisor\r | |
| 51 | .1:\r | |
| 52 | shr edx, 1\r | |
| 53 | rcr eax, 1\r | |
| 54 | shrd ebx, ecx, 1\r | |
| 55 | shr ecx, 1\r | |
| 56 | jnz .1\r | |
| 57 | div ebx\r | |
| 58 | mov ebx, eax ; ebx <- quotient\r | |
| 59 | mov ecx, [esp + 28] ; ecx <- high dword of divisor\r | |
| 60 | mul dword [esp + 24] ; edx:eax <- quotient * divisor[0..31]\r | |
| 61 | imul ecx, ebx ; ecx <- quotient * divisor[32..63]\r | |
| 62 | add edx, ecx ; edx <- (quotient * divisor)[32..63]\r | |
| 63 | mov ecx, dword [esp + 32] ; ecx <- addr for Remainder\r | |
| 64 | jc @TooLarge ; product > 2^64\r | |
| 65 | cmp edi, edx ; compare high 32 bits\r | |
| 66 | ja @Correct\r | |
| 67 | jb @TooLarge ; product > dividend\r | |
| 68 | cmp esi, eax\r | |
| 69 | jae @Correct ; product <= dividend\r | |
| 70 | @TooLarge:\r | |
| 71 | dec ebx ; adjust quotient by -1\r | |
| 72 | jecxz @Return ; return if Remainder == NULL\r | |
| 73 | sub eax, dword [esp + 24]\r | |
| 74 | sbb edx, dword [esp + 28] ; edx:eax <- (quotient - 1) * divisor\r | |
| 75 | @Correct:\r | |
| 76 | jecxz @Return\r | |
| 77 | sub esi, eax\r | |
| 78 | sbb edi, edx ; edi:esi <- remainder\r | |
| 79 | mov [ecx], esi\r | |
| 80 | mov [ecx + 4], edi\r | |
| 81 | @Return:\r | |
| 82 | mov eax, ebx ; eax <- quotient\r | |
| 83 | xor edx, edx ; quotient is 32 bits long\r | |
| 84 | pop edi\r | |
| 85 | pop esi\r | |
| 86 | pop ebx\r | |
| 87 | ret\r | |
| 88 | \r |