PNX1300 Philips, PNX1300 Datasheet - Page 340

• Manufacturer Part Number: PNX1300
• Description: Media Processors
• Manufacturer: Philips

Philips Semiconductors
Floating-point divide
SYNTAX
FUNCTION
DESCRIPTION
single-precision floating-point format. Rounding is according to the IEEE rounding mode bits in PCSW. If an argument
is denormalized, zero is substituted for the argument before computing the quotient, and the IFZ flag in the PCSW is
set. If the result is denormalized, the result is set to zero instead, and the OFZ flag in the PCSW is set. If
an IEEE exception, the corresponding exception flags in the PCSW are set. The PCSW exception flags are sticky: the
flags can be set as a side-effect of any floating-point operation but can only be reset by an explicit
operation. The update of the PCSW exception flags occurs at the same time as r dest is written. If any other floating-
point compute operations update the PCSW at the same time, the net result in each exception flag is the logical OR of
all simultaneous updates ORed with the existing PCSW value for that exception flag.
modification of the destination register. If the LSB of r guard is 1, rdest and the exception flags in PCSW are written;
otherwise, rdest is not changed and the operation does not affect the exception flags in PCSW.
EXAMPLES
r60 = 0xc0400000 (–3.0),
r30 = 0x3f800000 (1.0)
r40 = 0x40400000 (3.0),
r60 = 0xc0400000 (–3.0)
r10 = 0, r40 = 0x40400000 (3.0),
r80 = 0x00800000 (1.17549435e–38)
r20 = 1, r40 = 0x40400000 (3.0),
r80 = 0x00800000 (1.17549435e–38)
r40 = 0x40400000 (3.0),
r81 = 0x00400000 (5.877471754e–39)
r82 = 0x00c00000 (1.763241526e–38),
r83 = 0x80800000 (–1.175494351e–38)
r84 = 0x7f800000 (+INF),
r85 = 0xff800000 (–INF)
r70 = 0x7f7fffff (3.402823466e+38)
r80 = 0x00800000 (1.763241526e–38)
r75 = 0x40400000 (3.0),
r76 = 0x0 (0.0)
The
The
The
[ IF rguard ] fdiv rsrc1 rsrc2
if rguard then
fdivflags
fdiv
rdest
fdiv
Initial Values
operation computes the quotient rsrc1 rsrc2 and stores the result into rdest. All values are in IEEE
operation optionally takes a guard, specified in rguard. If a guard is present, its LSB controls the
(float)rsrc1 / (float)rsrc2
operation computes the exception flags that would result from an individual
fdiv r60 r30
fdiv r40 r60
IF r10 fdiv r40 r80
IF r20 fdiv r40 r80
fdiv r40 r81
fdiv r82 r83
fdiv r84 r85
fdiv r70 r70
fdiv r80 r80
fdiv r75 r76
rdest
Operation
r90
r95
r111
r112
r113
r120
r125
r126
PRELIMINARY SPECIFICATION
r100
r110
PNX1300/01/02/11 DSPCPU Operations
r90
r95
no change, since guard is false
r110
r111
r112
r113
r120
r125
r126
0xc0400000 (–3.0)
0xbf800000 (–1.0)
Function unit
Operation code
Number of operands
Modifier
Modifier range
Latency
Recovery
Issue slots
0x7f400000 (2.552117754e38)
0x7f800000 (+INF), IFZ, DBZ flags set
0xbfc00000 (-1.5)
0xffffffff (QNaN), INV flag set
0x3f800000 (1.0)
0x3f800000 (1.0)
0x7f800000 (+INF), DBZ flag set
fdivflags readpcsw
ATTRIBUTES
writepcsw
SEE ALSO
Result
fdiv
.
fdiv
writepcsw
ftough
fdiv
108
No
17
16
—
causes
2
2
A-42