| [41] | 1 | ; Project name : Assembly Library
|
|---|
| 2 | ; Description : Functions for bit handling.
|
|---|
| 3 |
|
|---|
| [376] | 4 | ;
|
|---|
| [526] | 5 | ; XTIDE Universal BIOS and Associated Tools
|
|---|
| 6 | ; Copyright (C) 2009-2010 by Tomi Tilli, 2011-2013 by XTIDE Universal BIOS Team.
|
|---|
| [376] | 7 | ;
|
|---|
| 8 | ; This program is free software; you can redistribute it and/or modify
|
|---|
| 9 | ; it under the terms of the GNU General Public License as published by
|
|---|
| 10 | ; the Free Software Foundation; either version 2 of the License, or
|
|---|
| 11 | ; (at your option) any later version.
|
|---|
| [526] | 12 | ;
|
|---|
| [376] | 13 | ; This program is distributed in the hope that it will be useful,
|
|---|
| 14 | ; but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|---|
| 15 | ; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|---|
| [526] | 16 | ; GNU General Public License for more details.
|
|---|
| [376] | 17 | ; Visit http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
|
|---|
| [526] | 18 | ;
|
|---|
| [376] | 19 |
|
|---|
| [41] | 20 | ; Section containing code
|
|---|
| 21 | SECTION .text
|
|---|
| 22 |
|
|---|
| 23 | ;--------------------------------------------------------------------
|
|---|
| 24 | ; Bit_GetSetCountToCXfromDXAX
|
|---|
| 25 | ; Parameters
|
|---|
| 26 | ; DX:AX: Source DWORD
|
|---|
| 27 | ; Returns:
|
|---|
| 28 | ; CX: Number of bits set in DX:AX
|
|---|
| 29 | ; Corrupts registers:
|
|---|
| 30 | ; Nothing
|
|---|
| 31 | ;--------------------------------------------------------------------
|
|---|
| 32 | ALIGN JUMP_ALIGN
|
|---|
| 33 | Bit_GetSetCountToCXfromDXAX:
|
|---|
| 34 | push bx
|
|---|
| 35 |
|
|---|
| 36 | call Bit_GetSetCountToCXfromAX
|
|---|
| 37 | mov bx, cx
|
|---|
| 38 | xchg ax, dx
|
|---|
| 39 | call Bit_GetSetCountToCXfromAX
|
|---|
| 40 | xchg ax, dx
|
|---|
| 41 | add cx, bx
|
|---|
| 42 |
|
|---|
| 43 | pop bx
|
|---|
| 44 | ret
|
|---|
| 45 |
|
|---|
| 46 |
|
|---|
| 47 | ;--------------------------------------------------------------------
|
|---|
| 48 | ; Bit_GetSetCountToCXfromAX
|
|---|
| 49 | ; Parameters
|
|---|
| 50 | ; AX: Source WORD
|
|---|
| 51 | ; Returns:
|
|---|
| 52 | ; CX: Number of bits set in AX
|
|---|
| 53 | ; Corrupts registers:
|
|---|
| 54 | ; Nothing
|
|---|
| 55 | ;--------------------------------------------------------------------
|
|---|
| 56 | ALIGN JUMP_ALIGN
|
|---|
| 57 | Bit_GetSetCountToCXfromAX:
|
|---|
| 58 | push ax
|
|---|
| 59 |
|
|---|
| 60 | xor cx, cx
|
|---|
| 61 | ALIGN JUMP_ALIGN
|
|---|
| 62 | .BitScanLoop:
|
|---|
| 63 | shr ax, 1
|
|---|
| 64 | jz SHORT .LastBitInCF
|
|---|
| [103] | 65 | adc cl, ch
|
|---|
| [41] | 66 | jmp SHORT .BitScanLoop
|
|---|
| 67 | ALIGN JUMP_ALIGN
|
|---|
| 68 | .LastBitInCF:
|
|---|
| [103] | 69 | adc cl, ch
|
|---|
| [41] | 70 |
|
|---|
| 71 | pop ax
|
|---|
| 72 | ret
|
|---|
| 73 |
|
|---|
| 74 |
|
|---|
| 75 | ;--------------------------------------------------------------------
|
|---|
| 76 | ; Bit_SetToDXAXfromIndexInCL
|
|---|
| 77 | ; Parameters:
|
|---|
| 78 | ; CL: Index of bit to set (0...31)
|
|---|
| 79 | ; DX:AX: Destination DWORD with flag to be set
|
|---|
| 80 | ; Returns:
|
|---|
| 81 | ; DX:AX: DWORD with wanted bit set
|
|---|
| 82 | ; Corrupts registers:
|
|---|
| 83 | ; Nothing
|
|---|
| 84 | ;--------------------------------------------------------------------
|
|---|
| 85 | ALIGN JUMP_ALIGN
|
|---|
| 86 | Bit_SetToDXAXfromIndexInCL:
|
|---|
| 87 | cmp cl, 16
|
|---|
| 88 | jb SHORT Bit_SetToAXfromIndexInCL
|
|---|
| 89 |
|
|---|
| 90 | sub cl, 16
|
|---|
| 91 | xchg ax, dx
|
|---|
| 92 | call Bit_SetToAXfromIndexInCL
|
|---|
| 93 | xchg dx, ax
|
|---|
| 94 | add cl, 16
|
|---|
| 95 | ret
|
|---|
| 96 |
|
|---|
| 97 | ;--------------------------------------------------------------------
|
|---|
| 98 | ; Bit_SetToAXfromIndexInCL
|
|---|
| 99 | ; Parameters:
|
|---|
| 100 | ; CL: Index of bit to set (0...15)
|
|---|
| 101 | ; AX: Destination WORD with flag to be set
|
|---|
| 102 | ; Returns:
|
|---|
| 103 | ; AX: WORD with wanted bit set
|
|---|
| 104 | ; Corrupts registers:
|
|---|
| 105 | ; Nothing
|
|---|
| 106 | ;--------------------------------------------------------------------
|
|---|
| 107 | ALIGN JUMP_ALIGN
|
|---|
| 108 | Bit_SetToAXfromIndexInCL:
|
|---|
| 109 | push dx
|
|---|
| 110 |
|
|---|
| 111 | mov dx, 1
|
|---|
| 112 | shl dx, cl
|
|---|
| 113 | or ax, dx
|
|---|
| 114 |
|
|---|
| 115 | pop dx
|
|---|
| 116 | ret
|
|---|
