Floating Point Instructions
5-98 M68000 FAMILY PROGRAMMER’S REFERENCE MANUAL MOTOROLA
FNEG Floating-Point Negate FNEG
(MC6888X, MC68040)
Operation: – (Source) → FPn
Assembler FNEG. < fmt > < ea > ,FPn
Syntax: FNEG.X FPm,FPn
FNEG.X FPn
*FrNEG. < fmt > < ea > ,FPn
*FrNEG.X FPm,FPn
*FrNEG.X FPn
where r is rounding precision, S or D
*Supported by MC68040 only
Attributes: Format = (Byte, Word, Long, Single, Double, Extended, Packed)
Description: Converts the source operand to extended precision (if necessary) and inverts
the sign of the mantissa. Stores the result in the destination floating-point data register.
FNEG will round the result to the precision selected in the floating-point control register.
FSNEG and FDNEG will round the result to single or double precision, respectively,
regardless of the rounding precision selected in the floating-point control register.
Operation Table:
NOTE: If the source operand is a NAN, refer to 1.6.5 Not-A-Numbers for more information.
DESTINATION
SOURCE
+ In Range – + Zero – + Infinity –
Result Negate
– 0.0 + 0.0 – inf + inf
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