assembler.txt

一个可以制作出和DELPHI很接近的IDE的好控健。只是稍微老了点。

; *******************************************************
; *                                                     *
; *     Delphi Runtime Library                          *
; *                                                     *
; *     Copyright (c) 1996,98 Inprise Corporation       *
; *                                                     *
; *******************************************************

    INCLUDE SE.ASM


    .386
    .MODEL  FLAT

    EXTRN   _Pow10:NEAR

    PUBLIC  _ValExt, @_ValExt

    .CODE

;   FUNCTION _ValExt( s: AnsiString; VAR code: Integer ) : Extended;

_ValExt PROC
@_ValExt:

; ->    EAX     Pointer to string
;       EDX     Pointer to code result
; <-    FST(0)  Result

    PUSH    EBX
    PUSH    ESI
    PUSH    EDI


    MOV     ESI,EAX
    PUSH    EAX             ; save for the error case

    FLDZ
    XOR     EAX,EAX
    XOR     EBX,EBX
    XOR     EDI,EDI

    PUSH    EBX             ; temp to get digs to fpu

    TEST    ESI,ESI
    JE      @@empty

@@blankLoop:
    MOV     BL,[ESI]
    INC     ESI
    CMP     BL,' '
    JE      @@blankLoop

@@endBlanks:
    MOV     CH,0
    CMP     BL,'-'
    JE      @@minus
    CMP     BL,'+'
    JE      @@plus
    JMP     @@firstDigit

@@minus:
    INC     CH
@@plus:
    MOV     BL,[ESI]
    INC     ESI

@@firstDigit:
    TEST    BL,BL
    JE      @@error

@@digLoop:
    SUB     BL,'0'
    CMP     BL,9
    JA      @@dotExp
    FMUL    ten
    MOV     dword ptr [ESP],EBX
    FIADD   dword ptr [ESP]

    MOV     BL,[ESI]
    INC     ESI

    TEST    BL,BL
    JNE     @@digLoop

    JMP     @@finish

@@dotExp:
    CMP     BL,'.' - '0'
    JNE     @@exp

    MOV     BL,[ESI]
    INC     ESI

    TEST    BL,BL
    JE      @@finish

@@fracDigLoop:
    SUB     BL,'0'
    CMP     BL,9
    JA      @@exp
    FMUL    ten
    MOV     dword ptr [ESP],EBX
    FIADD   dword ptr [ESP]
    DEC     EAX

    MOV     BL,[ESI]
    INC     ESI

    TEST    BL,BL
    JNE     @@fracDigLoop
    JMP     @@finish

@@exp:
    CMP     BL,'E' - '0'
    JE      @@foundExp
    CMP     BL,'e' - '0'
    JNE     @@error
@@foundExp:
    MOV     BL,[ESI]
    INC     ESI
    MOV     AH,0
    CMP     BL,'-'
    JE      @@minusExp
    CMP     BL,'+'
    JE      @@plusExp
    JMP     @@firstExpDigit
@@minusExp:
    INC     AH
@@plusExp:
    MOV     BL,[ESI]
    INC     ESI
@@firstExpDigit:
    SUB     BL,'0'
    CMP     BL,9
    JA      @@error
    MOV     EDI,EBX
    MOV     BL,[ESI]
    INC     ESI
    TEST    BL,BL
    JZ      @@endExp
@@expDigLoop:
    SUB     BL,'0'
    CMP     BL,9
    JA      @@error
    LEA     EDI,[EDI+EDI*4]
    ADD     EDI,EDI
    ADD     EDI,EBX
    MOV     BL,[ESI]
    INC     ESI
    TEST    BL,BL
    JNZ     @@expDigLoop
@@endExp:
    DEC     AH
    JNZ     @@expPositive
    NEG     EDI
@@expPositive:
    MOVSX   EAX,AL

@@finish:
    ADD     EAX,EDI
    PUSH    EDX
    PUSH    ECX
    CALL    _Pow10
    POP     ECX
    POP     EDX

    DEC     CH
    JE      @@negate

@@successExit:

    ADD     ESP,8           ; pop temp and saved copy of string pointer

    XOR     ESI,ESI         ; signal no error to caller

@@exit:
    MOV     [EDX],ESI

    POP     EDI
    POP     ESI
    POP     EBX
    RET

@@negate:
    FCHS
    JMP     @@successExit

@@empty:
    INC     ESI

@@error:
    POP     EAX
    POP     EBX
    SUB     ESI,EBX
    JMP     @@exit

ten DQ      10.0

_ValExt ENDP

    END