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91 lines
2.4 KiB
Plaintext
91 lines
2.4 KiB
Plaintext
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; File: FixMath.a
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;
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; Version 2.0a3
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;
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; Copyright 1984, 1985, 1986 Apple Computer, Inc. All Rights Reserved
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;
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INCLUDE 'SysEqu.a'
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; This file is the implementation of the FixMath calls.
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; FUNCTION FixDiv (x, y: Fixed): Fixed; { returns x/y, signed }
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;
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; FUNCTION FracDiv (x, y: Fracd): Fracd; { returns x/y }
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;
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; FUNCTION FracMul (x, y: Fracd): Fracd; { returns x*y }
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;
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; FUNCTION FracSqrt (x: Fracd) : Fracd; { returns square root of x }
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;
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; FUNCTION FracSin (x: Fixed) : Fracd; { returns Sin(x) }
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;
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; FUNCTION FracCos (x: Fixed) : Fracd; { returns Cos(x) }
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;
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; Type Fixed is 32-bit binary fixed-point with binary point between
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; high and low words. Sign is kept a la 2's-complement.
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; Type double is 64-bit IEEE binary floating point.
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; Type Fracd is 32-bit binary fixed point-point with binary point
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; after leading bits. Sign is kept a la 2's-complement.
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;
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; Exceptional cases:
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; Fixed overflow is set to $7FFFFFFF when positive, $80000000 when
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; negative.
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; Division by zero yields $7FFFFFFF when x is positive or zero,
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; and $80000000 when x is negative.
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;
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; Calling conventions:
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; Fixed results are returned in D0.32, double results in D0-D1.
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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; There are two flavors of multiply, FracMul and FixMul. FracMul uses the
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; top 35 bits of the 64-bit product: the top two are shifted off the left,
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; the the last bit is used for rounding. FixMul uses the middle 32 bits
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; of the product, with the attendant overflow checks, and rounds with a
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; 32nd bit.
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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;128K Rom Fixmath Traps with auto-pop bit set
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_NFracDiv OPWORD $AC4B
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_NFixDiv OPWORD $AC4D
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_NFracCos OPWORD $AC47
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_NFracSin OPWORD $AC48
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_NFracMul OPWORD $AC4A
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_NFracSqrt OPWORD $AC49
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FixMath PROC EXPORT
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EXPORT FracMul
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EXPORT FracDiv
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EXPORT FixDiv
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EXPORT FracSqrt
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EXPORT FracSin
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EXPORT FracCos
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FracMul
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_NFracMul ;the trap
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;will return to caller
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FracDiv
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_NFracDiv ;the trap
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;will return to caller
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FixDiv
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_NFixDiv ;the trap
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;will return to caller
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FracSqrt
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_NFracSqrt ;the trap
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;will return to caller
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FracCos
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_NFracCos ;the trap
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;will return to caller
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FracSin
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_NFracSin ;the trap
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;will return to caller
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END
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