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110 lines
5.5 KiB
ArmAsm
110 lines
5.5 KiB
ArmAsm
ttl ieee format equivalent abs and neg (iefabs/iefneg)
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***************************************
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* (c) copyright 1981 by motorola inc. *
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***************************************
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*************************************************************
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* iefabs *
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* fast floating point ieee format equivalent absolute value*
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* *
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* input: d7 - ieee format number argument *
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* *
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* output: d7 - ieee format number absolute value result *
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* *
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* condition codes: *
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* n - cleared *
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* z - set if result is zero *
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* v - set if result is nan (not-a-number) *
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* (occurs only if input argument is nan) *
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* c - undefined *
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* x - undefined *
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* *
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* all registers transparent *
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* *
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* maximum stack used: 24 bytes *
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* *
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* notes: *
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* 1) this routine properly handles all ieee floating *
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* point values and number types. *
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* 2) if the input argument is a nan (not-a-number) then *
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* it will be returned as the result with the "v" bit *
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* set in the condition code register. *
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* *
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*************************************************************
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page
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iefabs idnt 1,1 ieee format equivalent abs and neg
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opt pcs
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xdef iefabs ieee format absolute value
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xref iefsop single argument conversion routine
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xref iefrtod7 return caller's original d7 as result
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xref ffpcpyrt copyright notice
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section 9
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******************************
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* absolute value entry point *
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******************************
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iefabs jsr iefsop direct return to caller if nan encountered
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nop +0 normalized return (or zero or denormalized)
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* +2 infinity return
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* all values may be absolutized by forcing a plus sign on the original value
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bclr.b #7,16(sp) clear sign bit of original value
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jmp iefrtod7 and return original value altered a wee bit
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page
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*************************************************************
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* iefneg *
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* fast floating point ieee format equivalent negate *
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* *
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* input: d7 - ieee format number argument *
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* *
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* output: d7 - ieee format number negated result *
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* *
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* condition codes: *
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* n - set if result is negative *
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* z - set if result is zero *
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* v - set if result is nan (not-a-number) *
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* (occurs only if input argument is nan) *
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* c - undefined *
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* x - undefined *
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* *
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* all registers transparent *
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* *
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* maximum stack used: 24 bytes *
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* *
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* notes: *
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* 1) this routine properly handles all ieee floating *
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* point values and number types. *
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* 2) if the input argument is a nan (not-a-number) then *
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* it will be returned as the result with the "v" bit *
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* set in the condition code register. *
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* *
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*************************************************************
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page
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xdef iefneg ieee format negate
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**********************
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* negate entry point *
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**********************
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iefneg jsr iefsop direct return to caller if nan encountered
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nop +0 normalized return (or zero or denormalized)
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* +6 both infinity return
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* all values may be negated by inverting the sign bit of the original value
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bchg.b #7,16(sp) negate original sign bit
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jmp iefrtod7 and return this modified original register
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end
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jmp iefrtod7 and return this modified original register
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end
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jmp iefrtod7 and return this modified original register
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end
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jmp iefrtod7 and return this modified original register
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end
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