[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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| 47 | ALIGN JUMP_ALIGN |
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[46] | 48 | Memory_CopyCXbytesFromDSSItoESDI: |
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| 49 | OPTIMIZE_STRING_OPERATION rep, movs |
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| 50 | ret |
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[41] | 51 | |
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[46] | 52 | |
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[41] | 53 | ;-------------------------------------------------------------------- |
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[46] | 54 | ; Memory_ZeroSSBPwithSizeInCX |
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[41] | 55 | ; Parameters |
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[46] | 56 | ; CX: Number of bytes to zero |
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[41] | 57 | ; SS:BP: Ptr to buffer to zero |
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| 58 | ; Returns: |
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| 59 | ; Nothing |
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| 60 | ; Corrupts registers: |
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| 61 | ; Nothing |
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| 62 | ;-------------------------------------------------------------------- |
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| 63 | ALIGN JUMP_ALIGN |
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[46] | 64 | Memory_ZeroSSBPwithSizeInCX: |
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[50] | 65 | push es |
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| 66 | push di |
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[41] | 67 | push ax |
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[103] | 68 | Registers_CopySSBPtoESDI |
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[46] | 69 | call Memory_ZeroESDIwithSizeInCX |
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[41] | 70 | pop ax |
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[50] | 71 | pop di |
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| 72 | pop es |
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[41] | 73 | ret |
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| 74 | |
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| 75 | ;-------------------------------------------------------------------- |
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[46] | 76 | ; Memory_ZeroESDIwithSizeInCX |
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[41] | 77 | ; Parameters |
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[46] | 78 | ; CX: Number of bytes to zero |
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| 79 | ; ES:DI: Ptr to destination buffer |
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[41] | 80 | ; Returns: |
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[50] | 81 | ; DI: Updated by number of BYTEs stored |
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[41] | 82 | ; Corrupts registers: |
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| 83 | ; AX |
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| 84 | ;-------------------------------------------------------------------- |
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| 85 | ALIGN JUMP_ALIGN |
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[46] | 86 | Memory_ZeroESDIwithSizeInCX: |
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[41] | 87 | xor ax, ax |
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[46] | 88 | ; Fall to Memory_StoreCXbytesFromAccumToESDI |
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[41] | 89 | |
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| 90 | ;-------------------------------------------------------------------- |
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[46] | 91 | ; Memory_StoreCXbytesFromAccumToESDI |
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[41] | 92 | ; Parameters |
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| 93 | ; AX: Word to use to fill buffer |
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[46] | 94 | ; CX: Number of BYTEs to store |
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| 95 | ; ES:DI: Ptr to destination buffer |
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[41] | 96 | ; Returns: |
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[50] | 97 | ; DI: Updated by number of BYTEs stored |
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[41] | 98 | ; Corrupts registers: |
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| 99 | ; Nothing |
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| 100 | ;-------------------------------------------------------------------- |
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| 101 | ALIGN JUMP_ALIGN |
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[46] | 102 | Memory_StoreCXbytesFromAccumToESDI: |
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| 103 | OPTIMIZE_STRING_OPERATION rep, stos |
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[41] | 104 | ret |
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| 105 | |
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| 106 | |
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| 107 | ;-------------------------------------------------------------------- |
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| 108 | ; Memory_ReserveCXbytesFromStackToDSSI |
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| 109 | ; Parameters |
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| 110 | ; CX: Number of bytes to reserve |
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| 111 | ; Returns: |
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| 112 | ; DS:SI: Ptr to reserved buffer |
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| 113 | ; Corrupts registers: |
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| 114 | ; AX |
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| 115 | ;-------------------------------------------------------------------- |
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| 116 | ALIGN JUMP_ALIGN |
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| 117 | Memory_ReserveCXbytesFromStackToDSSI: |
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| 118 | pop ax |
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| 119 | push ss |
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| 120 | pop ds |
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| 121 | sub sp, cx |
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| 122 | mov si, sp |
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| 123 | jmp ax |
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