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96 lines
4.4 KiB
ArmAsm
96 lines
4.4 KiB
ArmAsm
ttl ieee format equivalent square root (iefsqrt)
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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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* iefsqrt *
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* ieee format equivalent square root *
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* *
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* input: *
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* d7 - ieee format argument *
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* *
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* output: *
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* d7 - ieee format square root *
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* *
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* condition codes: *
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* *
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* if the result is valid - *
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* n - cleared *
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* z - set if result is zero *
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* v - cleared *
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* c - undefined *
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* x - undefined *
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* *
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* if the result is invalid due to a *
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* negative non-zero or nan input argument- *
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* n - undefined *
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* z - cleared *
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* v - set *
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* c - undefined *
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* x - undefined *
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* *
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* all registers are 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) valid results are obtained unless *
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* the input argument was a negative *
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* non-zero number or nan (not-a- *
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* number) which can be determined by *
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* the "v" bit setting in the ccr. *
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* 2) see the mc68344 user's guide for *
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* details on the ranges handled by *
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* the fast floating point equivalent *
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* routines. *
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* *
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*************************************************
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page
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iefsqrt idnt 1,1 ieee format equivalent square root
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section 9
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xdef iefsqrt entry point
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xref ffpsqrt fast floating point square root routine
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xref iefsop single operand front-end handler
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xref ieftieee back-end handler to return ieee format
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xref iefrtnan error handler to return a nan (not-a-number)
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xref iefrtod7 return original caller's d7
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xref ffpcpyrt copyright notice
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*********************
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* square root entry *
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*********************
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iefsqrt jsr iefsop convert the operand
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bra.s iefnrm branch both normalized
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* argument was infinity - return a nan if minus
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* bmi iefrtnan return nan if it is minus infinity
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bmi dobranch
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jmp iefrtod7 just return input argument if plus infinity
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* argument was normalized
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* iefnrm bmi iefrtnan return nan for invalid negative argument
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iefnrm bmi dobranch
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move.l 16(sp),d5 insure was not a negative very small number
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bpl.s iefsdoit branch was positive
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add.l d5,d5 rid sign byte to check if was negative zero
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* bne iefrtnan return nan for very small negative numbers also
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bne dobranch
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iefsdoit jsr ffpsqrt perform square root
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jmp ieftieee and return ieee format back to caller
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dobranch:
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jmp iefrtnan 16-bit no MMU stuff
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end
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no MMU stuff
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end
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no MMU stuff
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end
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no MMU stuff
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end
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