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68343ffp.arc
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IEFEXP.SA
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1989-08-30
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3KB
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69 lines
TTL IEEE FORMAT EQUIVALENT EXPONENT (IEFEXP)
***************************************
* (C) COPYRIGHT 1981 BY MOTOROLA INC. *
***************************************
*************************************************
* IEFEXP *
* IEEE FORMAT EQUIVALENT EXPONENT FUNCTION *
* *
* INPUT: D7 - IEEE FLOATING POINT ARGUMENT *
* *
* OUTPUT: D7 - IEEE FLOATING POINT EXPONENTIAL*
* RESULT *
* *
* ALL OTHER REGISTERS ARE TRANSPARENT *
* *
* MAXIMUM STACK USED: 54 BYTES *
* *
* CONDITION CODES: *
* Z - SET IF RESULT IN D7 IS ZERO *
* N - CLEARED *
* V - SET IF RESULT IS NAN (NOT-A-NUMBER)*
* C - UNDEFINED *
* X - UNDEFINED *
* *
* *
* NOTES: *
* 1) IF THE INPUT ARGUMENT IS A NAN (NOT-A- *
* NUMBER) THEN THE "V" BIT WILL BE SET *
* AND THE ARGUMENT UNCHANGED UPON RETURN. *
* 2) SEE THE MC68344 USER'S GUIDE FOR DETAILS*
* ON THE RANGE OF IEEE NORMALIZED VALUES *
* SUPPORTED. *
* 2) SPOT CHECKS SHOW AT LEAST 6.8 DIGIT *
* ACCURACY FOR ALL ABS(ARG) < 30. *
* *
*************************************************
PAGE
IEFEXP IDNT 1,1 IEEE FORMAT EQUIVALENT EXP
OPT PCS
SECTION 9
XDEF IEFEXP ENTRY POINT
XREF 9:FFPEXP FAST FLOATING POINT EXPONENT
XREF 9:IEFSOP FRONT-END SINGLE ARGUMENT ROUTINE
XREF 9:IEFTIEEE BACK-END RETURN TO IEEE FORMAT
XREF 9:IEFRTD7 RETURN TO CALLER ARGUMENT IN D7
XREF FFPCPYRT COPYRIGHT STUB
************************
* EXPONENT ENTRY POINT *
************************
IEFEXP BSR IEFSOP CONVERT ARGUMENT TO FFP FORMAT
BRA.S IEFNRM BRANCH NORMALIZED
* ARGUMENT IS AN INFINITY
BPL.S IEFDRTN BRANCH IF PLUS - RETURN ITSELF
MOVE.L #0,D7 RETURN PLUS ZERO IF WAS NEGATIVE INFINITY
IEFDRTN BRA IEFRTD7 RETURN THE RESULT THAT IS IN D7
* ARGUMENT IS NORMALIZED
IEFNRM BSR FFPEXP CALL FAST FLOATING POINT EXPONENT FUNCTION
BRA IEFTIEEE AND RETURN IN IEEE FORMAT
END