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User’s Manual
IBM PowerPC 750GX and 750GL RISC Microprocessor
gx_02.fm.(1.2)
March 27, 2006
Programming Model
Page 85 of 377
Table 2-6 summarizes the mode behavior for results.
Don’t care
Single QNaN
Single SNaN
Double QNaN
Double SNaN
Don’t care QNaN
1
QNaN
1
Don’t care Don’t care
Single QNaN
Single SNaN
Double QNaN
Double SNaN
QNaN
1
QNaN
1
Single normalized
Single infinity
Single zero
Double normalized
Double infinity
Double zero
Single normalized
Single infinity
Single zero
Double normalized
Double infinity
Double zero
Single normalized
Single infinity
Single zero
Double normalized
Double infinity
Double zero
Do the operation Do the operation
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-
ing zeros.
Return zero.
Single
Normalized, infinity,
zero
Return the result. Return the result.
Single QNaN, SNaN Return QNaN. Return QNaN.
Single Integer Place integer into low word of FPR.
If (Invalid Operation)
then
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,
zero
Return the result. Return the result.
Double QNaN, SNaN Return QNaN. Return QNaN.
Double INT Not supported by the 750GX Not supported by the 750GX
Table 2-5. Floating-Point Operand Data-Type Behavior (Page 2 of 2)
Operand A
Data Type
Operand B
Data Type
Operand C
Data Type
IEEE Mode
(NI = 0)
Non-IEEE Mode
(NI = 1)
1. Prioritize according to Chapter 3, “Operand Conventions,” in the PowerPC Microprocessor Family: The Programming Environ-
ments Manual.