IBM powerpc 750gx 사용자 설명서

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

Don’t care

Single QNaN

Single SNaN

Double QNaN

Double SNaN

QNaN

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

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.

Single

QNaN, SNaN

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.

Double

QNaN, SNaN

Return QNaN.

Double

INT

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.