| 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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