| 1 | ; File name : String.asm |
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| 2 | ; Project name : Assembly Library |
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| 3 | ; Created date : 12.7.2010 |
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| 4 | ; Last update : 6.9.2010 |
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| 5 | ; Author : Tomi Tilli |
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| 6 | ; Description : Functions for handling characters. |
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| 7 | |
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| 8 | ; Section containing code |
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| 9 | SECTION .text |
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| 10 | |
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| 11 | ;-------------------------------------------------------------------- |
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| 12 | ; String_ConvertWordToAXfromStringInDSSIwithBaseInBX |
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| 13 | ; Parameters: |
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| 14 | ; BX: Numeric base (10 or 16) |
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| 15 | ; DS:SI: Ptr to string to convert |
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| 16 | ; Returns: |
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| 17 | ; AX: Word converted from string |
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| 18 | ; DI: Offset to NULL or first invalid character |
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| 19 | ; CF: Set if conversion successfull |
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| 20 | ; Cleared if invalid string |
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| 21 | ; Corrupts registers: |
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| 22 | ; DX |
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| 23 | ;-------------------------------------------------------------------- |
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| 24 | ALIGN JUMP_ALIGN |
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| 25 | String_ConvertWordToAXfromStringInDSSIwithBaseInBX: |
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| 26 | xor dx, dx |
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| 27 | cld |
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| 28 | |
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| 29 | ALIGN JUMP_ALIGN |
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| 30 | .ConvertWordToAXfromStringInDSSIwithBaseInBX: |
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| 31 | lodsb ; Load character from DS:SI to AL |
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| 32 | call Char_ConvertIntegerToALfromDigitInALwithBaseInBX |
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| 33 | jnc SHORT .InvalidCharacter |
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| 34 | xor ah, ah |
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| 35 | push ax ; Push integer |
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| 36 | xchg ax, dx ; Copy WORD to AX |
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| 37 | mul bx ; DX:AX = word in AX * base in BX |
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| 38 | pop dx ; Pop integer |
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| 39 | add dx, ax ; WORD back to DX |
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| 40 | jmp SHORT .ConvertWordToAXfromStringInDSSIwithBaseInBX |
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| 41 | |
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| 42 | ALIGN JUMP_ALIGN |
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| 43 | .InvalidCharacter: |
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| 44 | sub al, 1 ; Set CF if NULL character, clear CF otherwise |
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| 45 | xchg ax, dx ; Return WORD in AX |
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| 46 | ret |
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| 47 | |
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| 48 | |
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| 49 | ;-------------------------------------------------------------------- |
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| 50 | ; String_CopyToESDIfromDSSIwithoutTerminatingESDI |
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| 51 | ; Parameters: |
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| 52 | ; DS:SI: Ptr to source NULL terminated string |
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| 53 | ; ES:DI: Ptr to destination buffer |
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| 54 | ; Returns: |
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| 55 | ; CX: Number of characters copied |
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| 56 | ; SI,DI: Updated by CX characters |
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| 57 | ; Corrupts registers: |
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| 58 | ; Nothing |
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| 59 | ;-------------------------------------------------------------------- |
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| 60 | ALIGN JUMP_ALIGN |
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| 61 | String_CopyToESDIfromDSSIwithoutTerminatingESDI: |
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| 62 | push ax |
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| 63 | xor cx, cx |
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| 64 | |
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| 65 | ALIGN JUMP_ALIGN |
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| 66 | .GetAndStoreNewCharacter: |
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| 67 | lodsb ; Load from DS:SI to AL |
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| 68 | test al, al ; NULL to end string? |
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| 69 | jz SHORT .EndOfString |
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| 70 | stosb ; Store from AL to ES:DI |
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| 71 | inc cx ; Increment number of characters written |
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| 72 | jmp SHORT .GetAndStoreNewCharacter |
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| 73 | |
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| 74 | ALIGN JUMP_ALIGN |
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| 75 | .EndOfString: |
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| 76 | pop ax |
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| 77 | ret |
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