IBM 750GL, 750GX manual 85

User’s Manual

IBM PowerPC 750GX and 750GL RISC Microprocessor

Table 2-5. Floating-Point Operand Data-Type Behavior (Page 2 of 2)

Operand A	Operand B	Operand C	IEEE Mode	Non-IEEE Mode
Data Type	Data Type	Data Type	(NI = 0)	(NI = 1)
	Single QNaN
Don’t care	Single SNaN	Don’t care	QNaN1	QNaN1
	Double QNaN
	Double SNaN
		Single QNaN
Don’t care	Don’t care	Single SNaN	QNaN1	QNaN1
		Double QNaN
		Double SNaN
Single normalized	Single normalized	Single normalized
Single infinity	Single infinity	Single infinity
Single zero	Single zero	Single zero	Do the operation	Do the operation
Double normalized	Double normalized	Double normalized
Double infinity	Double infinity	Double infinity
Double zero	Double zero	Double zero

1.Prioritize according to Chapter 3, “Operand Conventions,” in the PowerPC Microprocessor Family: The Programming Environ- ments Manual.

Table 2-6summarizes the mode behavior for results.

Table 2-6. Floating-Point Result Data-Type Behavior

Precision	Data Type	IEEE Mode (NI = 0)	Non-IEEE Mode (NI = 1)
Single	Denormalized	Return single-precision denormalized number with trail-	Return zero.
		ing zeros.
Single	Normalized, infinity,	Return the result.	Return the result.
	zero
Single	QNaN, SNaN	Return QNaN.	Return QNaN.
			If (Invalid Operation)
			then
Single	Integer	Place integer into low word of FPR.	Place (0x8000) into FPR[32–63]
			else
			Place integer into FPR[32–63].
Double	Denormalized	Return double-precision denormalized number.	Return zero.
Double	Normalized, infinity,	Return the result.	Return the result.
	zero
Double	QNaN, SNaN	Return QNaN.	Return QNaN.
Double	INT	Not supported by the 750GX	Not supported by the 750GX

gx_02.fm.(1.2)	Programming Model
March 27, 2006	Page 85 of 377