| 1 | ; Project name : Assembly Library
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| 2 | ; Description : Functions for memory access.
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| 3 |
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| 4 | ;
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| 5 | ; XTIDE Universal BIOS and Associated Tools
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| 6 | ; Copyright (C) 2009-2010 by Tomi Tilli, 2011-2012 by XTIDE Universal BIOS Team.
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| 7 | ;
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| 8 | ; This program is free software; you can redistribute it and/or modify
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| 9 | ; it under the terms of the GNU General Public License as published by
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| 10 | ; the Free Software Foundation; either version 2 of the License, or
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| 11 | ; (at your option) any later version.
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| 12 | ;
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| 13 | ; This program is distributed in the hope that it will be useful,
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| 14 | ; but WITHOUT ANY WARRANTY; without even the implied warranty of
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| 15 | ; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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| 16 | ; GNU General Public License for more details.
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| 17 | ; Visit http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
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| 18 | ;
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| 19 |
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| 20 | ; Section containing code
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| 21 | SECTION .text
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| 22 |
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| 23 | ;--------------------------------------------------------------------
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| 24 | ; OPTIMIZE_STRING_OPERATION
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| 25 | ; Parameters
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| 26 | ; %1: Repeat instruction
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| 27 | ; %2: String instruction without size (for example MOVS and not MOVSB or MOVSW)
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| 28 | ; CX: Number of BYTEs to operate
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| 29 | ; DS:SI: Ptr to source data
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| 30 | ; ES:DI: Ptr to destination
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| 31 | ; Returns:
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| 32 | ; SI, DI: Updated by number of bytes operated
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| 33 | ; Corrupts registers:
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| 34 | ; Nothing
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| 35 | ;--------------------------------------------------------------------
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| 36 | %macro OPTIMIZE_STRING_OPERATION 2
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| 37 | push cx
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| 38 |
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| 39 | shr cx, 1 ; Operate with WORDs for performance
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| 40 | jz %%HandleRemainingByte
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| 41 | %1 %2w
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| 42 | %%HandleRemainingByte:
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| 43 | jnc SHORT %%OperationCompleted
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| 44 | %2b
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| 45 |
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| 46 | ALIGN JUMP_ALIGN
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| 47 | %%OperationCompleted:
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| 48 | pop cx
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| 49 | %endmacro
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| 50 |
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| 51 |
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| 52 | ;--------------------------------------------------------------------
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| 53 | ; Memory_CopyCXbytesFromDSSItoESDI
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| 54 | ; Parameters
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| 55 | ; CX: Number of bytes to copy
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| 56 | ; DS:SI: Ptr to source data
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| 57 | ; ES:DI: Ptr to destination buffer
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| 58 | ; Returns:
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| 59 | ; SI, DI: Updated by number of bytes copied
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| 60 | ; Corrupts registers:
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| 61 | ; Nothing
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| 62 | ;--------------------------------------------------------------------
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| 63 | %ifndef EXCLUDE_FROM_XTIDE_UNIVERSAL_BIOS
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| 64 | ALIGN JUMP_ALIGN
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| 65 | Memory_CopyCXbytesFromDSSItoESDI:
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| 66 | OPTIMIZE_STRING_OPERATION rep, movs
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| 67 | ret
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| 68 | %endif
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| 69 |
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| 70 |
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| 71 | ;--------------------------------------------------------------------
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| 72 | ; Memory_ZeroSSBPwithSizeInCX
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| 73 | ; Parameters
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| 74 | ; CX: Number of bytes to zero
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| 75 | ; SS:BP: Ptr to buffer to zero
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| 76 | ; Returns:
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| 77 | ; Nothing
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| 78 | ; Corrupts registers:
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| 79 | ; Nothing
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| 80 | ;--------------------------------------------------------------------
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| 81 | ALIGN JUMP_ALIGN
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| 82 | Memory_ZeroSSBPwithSizeInCX:
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| 83 | push es
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| 84 | push di
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| 85 | push ax
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| 86 | call Registers_CopySSBPtoESDI
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| 87 | call Memory_ZeroESDIwithSizeInCX
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| 88 | pop ax
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| 89 | pop di
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| 90 | pop es
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| 91 | ret
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| 92 |
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| 93 | ;--------------------------------------------------------------------
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| 94 | ; Memory_ZeroESDIwithSizeInCX
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| 95 | ; Parameters
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| 96 | ; CX: Number of bytes to zero
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| 97 | ; ES:DI: Ptr to destination buffer
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| 98 | ; Returns:
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| 99 | ; DI: Updated by number of BYTEs stored
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| 100 | ; Corrupts registers:
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| 101 | ; AX
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| 102 | ;--------------------------------------------------------------------
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| 103 | ALIGN JUMP_ALIGN
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| 104 | Memory_ZeroESDIwithSizeInCX:
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| 105 | xor ax, ax
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| 106 | ; Fall to Memory_StoreCXbytesFromAccumToESDI
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| 107 |
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| 108 | ;--------------------------------------------------------------------
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| 109 | ; Memory_StoreCXbytesFromAccumToESDI
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| 110 | ; Parameters
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| 111 | ; AX: Word to use to fill buffer
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| 112 | ; CX: Number of BYTEs to store
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| 113 | ; ES:DI: Ptr to destination buffer
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| 114 | ; Returns:
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| 115 | ; DI: Updated by number of BYTEs stored
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| 116 | ; Corrupts registers:
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| 117 | ; Nothing
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| 118 | ;--------------------------------------------------------------------
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| 119 | ALIGN JUMP_ALIGN
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| 120 | Memory_StoreCXbytesFromAccumToESDI:
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| 121 | OPTIMIZE_STRING_OPERATION rep, stos
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| 122 | ret
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| 123 |
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| 124 |
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| 125 | ;--------------------------------------------------------------------
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| 126 | ; Memory_ReserveCXbytesFromStackToDSSI
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| 127 | ; Parameters
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| 128 | ; CX: Number of bytes to reserve
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| 129 | ; Returns:
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| 130 | ; DS:SI: Ptr to reserved buffer
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| 131 | ; Corrupts registers:
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| 132 | ; AX
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| 133 | ;--------------------------------------------------------------------
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| 134 | %ifndef EXCLUDE_FROM_XTIDE_UNIVERSAL_BIOS
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| 135 | ALIGN JUMP_ALIGN
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| 136 | Memory_ReserveCXbytesFromStackToDSSI:
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| 137 | pop ax
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| 138 | push ss
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| 139 | pop ds
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| 140 | sub sp, cx
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| 141 | mov si, sp
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| 142 | jmp ax
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| 143 | %endif
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