76 lines
1.9 KiB
NASM
76 lines
1.9 KiB
NASM
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; Copyright (c) Mix Software 1988
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;
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; --------------------------------------------------
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; alloca - allocate from the stack
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; returns null if not enough memory
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; char *_alloca(size)
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; unsigned size;
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; --------------------------------------------------
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;
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IDT alloca
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DEF alloca
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DREF $$LIMIT
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DREF $$MAXS
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;
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alloca MOV SI,SP
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MOV AX,[SI][%PARM1-2] ; Requested size
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SUB SI,[$$LIMIT] ; Stack boundary
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CMP SI,AX
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JB NOSPACE
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POP BX ; Remove return
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POP CX
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POP DX ; argument
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SUB SP,AX
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MOV AX,SP
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DEC AX
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AND AX,>FFFE
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MOV SP,AX
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PUSH DX
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PUSH CX
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PUSH BX
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CMP AX,[$$MAXS]
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JAE EXIT
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MOV [$$MAXS],AX
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EXIT RETSEG
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NOSPACE XOR AX,AX
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RETSEG
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END
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;
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; --------------------------------------------------
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; stackavail - return available stack
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; returns amount of stack space available
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; unsigned stackavail()
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; --------------------------------------------------
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;
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IDT stackava
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IF LONGNAME
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LDEF stackavail
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ENDIF
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IF SHORTNAM
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DEF stackava
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ENDIF
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DREF $$LIMIT
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DREF $$MAXS
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;
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stackavail MOV AX,SP
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SUB AX,[$$LIMIT] ; Stack boundary
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RETSEG
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END
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;
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; --------------------------------------------------
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; stacksiz - return available stack
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; returns amount of stack space available
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; unsigned stacksiz()
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; --------------------------------------------------
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;
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IDT stacksiz
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DEF stacksiz
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DREF $$LIMIT
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DREF $$MAXS
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;
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stacksiz MOV AX,SP
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SUB AX,[$$LIMIT] ; Stack boundary
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RETSEG
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END
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