[41] | 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 | ; Section containing code
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| 5 | SECTION .text
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| 6 |
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| 7 | ;--------------------------------------------------------------------
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[46] | 8 | ; OPTIMIZE_STRING_OPERATION
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[41] | 9 | ; Parameters
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[46] | 10 | ; %1: Repeat instruction
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| 11 | ; %2: String instruction without size (for example MOVS and not MOVSB or MOVSW)
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| 12 | ; CX: Number of BYTEs to operate
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| 13 | ; DS:SI: Ptr to source data
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| 14 | ; ES:DI: Ptr to destination
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[41] | 15 | ; Returns:
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[46] | 16 | ; SI, DI: Updated by number of bytes operated
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| 17 | ; Corrupts registers:
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[41] | 18 | ; Nothing
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[46] | 19 | ;--------------------------------------------------------------------
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| 20 | %macro OPTIMIZE_STRING_OPERATION 2
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| 21 | push cx
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| 22 |
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| 23 | shr cx, 1 ; Operate with WORDs for performance
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[103] | 24 | jz %%HandleRemainingByte
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[46] | 25 | %1 %2w
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| 26 | %%HandleRemainingByte:
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| 27 | jnc SHORT %%OperationCompleted
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| 28 | %2b
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| 29 |
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| 30 | ALIGN JUMP_ALIGN
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| 31 | %%OperationCompleted:
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| 32 | pop cx
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| 33 | %endmacro
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| 34 |
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| 35 |
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| 36 | ;--------------------------------------------------------------------
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| 37 | ; Memory_CopyCXbytesFromDSSItoESDI
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| 38 | ; Parameters
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| 39 | ; CX: Number of bytes to copy
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| 40 | ; DS:SI: Ptr to source data
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| 41 | ; ES:DI: Ptr to destination buffer
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| 42 | ; Returns:
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| 43 | ; SI, DI: Updated by number of bytes copied
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[41] | 44 | ; Corrupts registers:
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[46] | 45 | ; Nothing
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[41] | 46 | ;--------------------------------------------------------------------
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[131] | 47 | %ifndef EXCLUDE_FROM_XTIDE_UNIVERSAL_BIOS
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[41] | 48 | ALIGN JUMP_ALIGN
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[46] | 49 | Memory_CopyCXbytesFromDSSItoESDI:
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| 50 | OPTIMIZE_STRING_OPERATION rep, movs
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| 51 | ret
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[131] | 52 | %endif
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[41] | 53 |
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[46] | 54 |
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[41] | 55 | ;--------------------------------------------------------------------
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[46] | 56 | ; Memory_ZeroSSBPwithSizeInCX
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[41] | 57 | ; Parameters
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[46] | 58 | ; CX: Number of bytes to zero
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[41] | 59 | ; SS:BP: Ptr to buffer to zero
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| 60 | ; Returns:
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| 61 | ; Nothing
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| 62 | ; Corrupts registers:
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| 63 | ; Nothing
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| 64 | ;--------------------------------------------------------------------
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| 65 | ALIGN JUMP_ALIGN
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[46] | 66 | Memory_ZeroSSBPwithSizeInCX:
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[50] | 67 | push es
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| 68 | push di
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[41] | 69 | push ax
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[105] | 70 | call Registers_CopySSBPtoESDI
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[46] | 71 | call Memory_ZeroESDIwithSizeInCX
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[41] | 72 | pop ax
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[50] | 73 | pop di
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| 74 | pop es
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[41] | 75 | ret
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| 76 |
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| 77 | ;--------------------------------------------------------------------
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[46] | 78 | ; Memory_ZeroESDIwithSizeInCX
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[41] | 79 | ; Parameters
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[46] | 80 | ; CX: Number of bytes to zero
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| 81 | ; ES:DI: Ptr to destination buffer
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[41] | 82 | ; Returns:
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[50] | 83 | ; DI: Updated by number of BYTEs stored
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[41] | 84 | ; Corrupts registers:
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| 85 | ; AX
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| 86 | ;--------------------------------------------------------------------
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| 87 | ALIGN JUMP_ALIGN
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[46] | 88 | Memory_ZeroESDIwithSizeInCX:
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[41] | 89 | xor ax, ax
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[46] | 90 | ; Fall to Memory_StoreCXbytesFromAccumToESDI
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[41] | 91 |
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| 92 | ;--------------------------------------------------------------------
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[46] | 93 | ; Memory_StoreCXbytesFromAccumToESDI
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[41] | 94 | ; Parameters
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| 95 | ; AX: Word to use to fill buffer
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[46] | 96 | ; CX: Number of BYTEs to store
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| 97 | ; ES:DI: Ptr to destination buffer
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[41] | 98 | ; Returns:
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[50] | 99 | ; DI: Updated by number of BYTEs stored
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[41] | 100 | ; Corrupts registers:
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| 101 | ; Nothing
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| 102 | ;--------------------------------------------------------------------
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| 103 | ALIGN JUMP_ALIGN
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[46] | 104 | Memory_StoreCXbytesFromAccumToESDI:
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| 105 | OPTIMIZE_STRING_OPERATION rep, stos
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[41] | 106 | ret
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| 107 |
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| 108 |
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| 109 | ;--------------------------------------------------------------------
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| 110 | ; Memory_ReserveCXbytesFromStackToDSSI
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| 111 | ; Parameters
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| 112 | ; CX: Number of bytes to reserve
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| 113 | ; Returns:
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| 114 | ; DS:SI: Ptr to reserved buffer
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| 115 | ; Corrupts registers:
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| 116 | ; AX
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| 117 | ;--------------------------------------------------------------------
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[194] | 118 | %ifndef EXCLUDE_FROM_XTIDE_UNIVERSAL_BIOS
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[41] | 119 | ALIGN JUMP_ALIGN
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| 120 | Memory_ReserveCXbytesFromStackToDSSI:
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| 121 | pop ax
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| 122 | push ss
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| 123 | pop ds
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| 124 | sub sp, cx
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| 125 | mov si, sp
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| 126 | jmp ax
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[194] | 127 | %endif
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