148 lines
3.5 KiB
NASM
148 lines
3.5 KiB
NASM
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; Copyright (c) Mix Software 1988
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;
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IF 0
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;
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; getenv - return a pointer to an entry in the environment
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;
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; char *getenv(varname)
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;
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; varname is the name of the variable (eg "PATH=")
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;
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IDT GETENV
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DEF GETENV
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DEF getenv
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DREF environ
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FREF _moveenv
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;
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getenv EQU $
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GETENV PUSH BP
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MOV BP,SP
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CMP [environ],0
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JNZ INITDONE
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CALLFAR _moveenv
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JZ NOFIND
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INITDONE MOV BX,environ
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MOV CX,-1
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MOV AX,DS
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MOV ES,AX
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CLD
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SRCH MOV DI,[BX]
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ADD BX,%2
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TEST DI,DI ; End of table?
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JZ NOFIND
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MOV SI,[BP][%PARM1]
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MOV CX,>7FFF
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REPZ ; Compare values
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CMPSB
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TEST %[SI][%-1],%>FF ; Equal to end of string mark?
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JNZ SRCH
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DEC DI
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MOV AX,DI
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POP BP
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RETSEG
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NOFIND XOR AX,AX
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POP BP
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RETSEG
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END
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;
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ENDIF
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;
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;
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; _moveenv - copy environment to the data segment
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; $$ENVIR has the segment pointer to the environment
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; environ is created to hold an array of pointers to the
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; environment strings.
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;
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IDT _moveenv
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DEF _moveenv
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DREF environ
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DREF $$ENVIR
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DREF $$ENVPX
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FREF malloc
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PEXTRA EQU 4 ; Number of extra pointer slots
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;
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_moveenv XOR DX,DX ; Counter for number of strings
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MOV ES,[$$ENVIR]
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XOR DI,DI
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MOV AL,%0
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MOV CX,-1
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CLD
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FINDLEN INC DX ; Count this string
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SEGES
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CMP %[DI],%0 ; end of table?
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JZ ENDENV
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REPNZ
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SCASB
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JMPS FINDLEN
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ENDENV NOT CX ; CX is size of the environment
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INC CX ; Make size even
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AND CX,>FFFE
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PUSH DX ; Save number of pointers
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PUSH CX
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CALLFAR malloc
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POP CX
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POP DX
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TEST AX,AX
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JZ NOSPACE
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MOV DI,AX
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PUSH DI
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MOV AX,DS
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MOV ES,AX
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MOV DS,[$$ENVIR]
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SHR CX,1
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XOR SI,SI
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REP ; Copy environment to heap
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MOVSW
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MOV AX,ES
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MOV DS,AX
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MOV CX,DX
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ADD CX,CX ; Memory required for array of pointers
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ADD CX,PEXTRA*2 ; Space for extra pointers
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PUSH DX
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PUSH CX
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CALLFAR malloc
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POP CX
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POP DX
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POP DI ; Address of environment block
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TEST AX,AX
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JZ NOSPACE
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MOV BX,AX ; Address of pointer array
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MOV [environ],AX
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MOV AX,DS
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MOV ES,AX
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MOV CX,-1
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MOV AL,%0
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COPYPTR DEC DX
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JZ DONE
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MOV [BX],DI
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ADD BX,%2
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REPNZ
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SCASB
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JMPS COPYPTR
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DONE MOV CX,PEXTRA+1
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FILL MOV [BX],0
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ADD BX,%2
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LOOP FILL
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MOV [$$ENVPX],PEXTRA
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MOV AX,[environ]
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RETSEG
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NOSPACE XOR AX,AX
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RETSEG
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END
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;
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; char *(*environ)[];
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; int $$ENVPX;
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; int $$ENVALT = 0;
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;
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IDT environ
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DDEF environ
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DDEF $$ENVPX
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DDEF $$ENVALT
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DORG 0
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environ dw 0
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$$ENVPX dw 0
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$$ENVALT dw 0
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END
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;
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