FUJITSU Implementation Supplement Fujitsu SPARC64 V User Manual

Page 63

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52

SPARC JPS1 Implementation Supplement: Fujitsu SPARC64 V • Release 1.0, 1 July 2002

detects any conditions for an

unfinished_FPop

trap, the Floating-point Multiply-Add/

Subtract instruction generates the

unfinished_FPop

exception. In this case, none of

rd

,

cexc

, or

aexc

are modified.

Detailed contents of

cexc

and

aexc

depending on the various conditions are

described in

TABLE A-3

and

TABLE A-4

. The following terminology is used: uf, of, inv,

and nx are nontrapping IEEE exception conditions—underflow, overflow, invalid
operation, and inexact, respectively.

In the tables, the conditions in the shaded columns are all reported as an

unfinished_FPop

trap by SPARC64 V. In addition, the conditions with “

” do not

exist.

TABLE A-2

Exceptions in Floating-Point Multiply-Add/Subtract Instructions

FMUL

IEEE754 trap

No trap

No trap

FADD/SUB

IEEE754 trap

No trap

cexc

Exception condition of

FMUL

Exception condition of

FADD

Logical or of the nontrapping exception
conditions of

FMUL

and

FADD/SUB

aexc

No change

No change

Logical OR of the

cexc

(above) and the

aexc

TABLE A-3

Non-Trapping

cexc

When

FSR.NS

= 0

FADD

none

nx

of nx

inv

FMUL

none

none

nx

of nx

inv

nx

nx

nx

of nx

inv nx

of nx

of nx

of nx

of nx

inv of nx

uf nx

uf nx

uf nx

uf of nx

uf inv nx

inv

inv

inv

TABLE A-4

Non-Trapping

aexc

When

FSR.NS

= 1

FADD

none

nx

of nx

uf nx

inv

FMUL

none

none

nx

of nx

uf nx

inv

nx

nx

nx

of nx

uf nx

inv nx

of nx

of nx

of nx

of nx

inv of nx

uf nx

uf nx

uf inv nx

inv

inv

inv

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