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68 lines
2.8 KiB
ArmAsm
68 lines
2.8 KiB
ArmAsm
ttl ieee format equivalent exponent (iefexp)
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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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* iefexp *
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* ieee format equivalent exponent function *
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* *
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* input: d7 - ieee floating point argument *
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* *
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* output: d7 - ieee floating point exponential*
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* result *
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* *
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* all other registers are transparent *
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* *
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* maximum stack used: 54 bytes *
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* *
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* condition codes: *
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* z - set if result in d7 is zero *
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* n - cleared *
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* v - set if result is nan (not-a-number)*
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* c - undefined *
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* x - undefined *
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* *
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* *
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* notes: *
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* 1) if the input argument is a nan (not-a- *
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* number) then the "v" bit will be set *
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* and the argument unchanged upon return. *
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* 2) see the mc68344 user's guide for details*
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* on the range of ieee normalized values *
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* supported. *
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* 2) spot checks show at least 6.8 digit *
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* accuracy for all abs(arg) < 30. *
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* *
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*************************************************
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page
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iefexp idnt 1,1 ieee format equivalent exp
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opt pcs
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section 9
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xdef iefexp entry point
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xref ffpexp fast floating point exponent
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xref iefsop front-end single argument routine
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xref ieftieee back-end return to ieee format
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xref iefrtd7 return to caller argument in d7
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xref ffpcpyrt copyright stub
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************************
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* exponent entry point *
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************************
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iefexp jsr iefsop convert argument to ffp format
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bra.s iefnrm branch normalized
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* argument is an infinity
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bpl.s iefdrtn branch if plus - return itself
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move.l #0,d7 return plus zero if was negative infinity
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iefdrtn jmp iefrtd7 return the result that is in d7
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* argument is normalized
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iefnrm jsr ffpexp call fast floating point exponent function
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jmp ieftieee and return in ieee format
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end
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