PNX1301 PHILIPS [NXP Semiconductors], PNX1301 Datasheet - Page 326

• Manufacturer Part Number: PNX1301
• Description: Media Processors
• Manufacturer: PHILIPS [NXP Semiconductors]

Philips Semiconductors
Dual clipped subtract of signed 16-bit halfwords
SYNTAX
FUNCTION
DESCRIPTION
two pairs of high and low 16-bit halfwords of rsrc1 and rsrc2. Both differences are clipped into the range [2
(or [0x7fff..0x8000]) and written into the corresponding halfwords of rdest. All values are signed 16-bit integers.
the modification of the destination register. If the LSB of rguard is 1, rdest is written; otherwise, rdest is not changed.
EXAMPLES
r30 = 0x12340032, r40 = 0x00010002
r10 = 0, r30 = 0x12340032, r40 = 0x00010002
r20 = 1, r30 = 0x12340032, r40 = 0x00010002
r50 = 0x80000001, r80 = 0x00018001
r110 = 0x00018001, r120 = 0x80010002
As shown below, the
The
[ IF rguard ] dspidualsub rsrc1 rsrc2
if rguard then {
}
rsrc1
temp1
temp2
if temp1 < 0xffff8000 then temp1
if temp2 < 0xffff8000 then temp2
if temp1 > 0x7fff then temp1
if temp2 > 0x7fff then temp2
rdest<31:16>
rdest<15:0>
dspidualsub
31
sign_ext16to32(rsrc1<15:0>) – sign_ext16to32(rsrc2<15:0>)
sign_ext16to32(rsrc1<31:16>) – sign_ext16to32(rsrc2<31:16>)
17-bit signed differences
signed
Initial Values
temp1<15:0>
Two full-precision
temp2<15:0>
dspidualsub
operation optionally takes a guard, specified in rguard. If a guard is present, its LSB controls
15
rdest
0x7fff
0x7fff
17
0x8000
0x8000
31
signed
Clip to [2
operation computes two 16-bit clipped, signed differences separately on the
signed
dspidualsub r30 r40
IF r10 dspidualsub r30 r40
IF r20 dspidualsub r30 r40
dspidualsub r50 r80
dspidualsub r110 r120
15
signed
–1..–2
0
15
]
0
rdest
15
17
PRELIMINARY SPECIFICATION
rsrc2
Operation
Clip to [2
31
signed
signed
PNX1300/01/02/11 DSPCPU Operations
15
–1..–2
signed
r60
r90
r125
15
]
0
Function unit
Operation code
Number of operands
Modifier
Modifier range
Latency
Issue slots
0
dspidualabs dspidualadd
r70
r100
dspidualmul dspiabs
15
dspidualsub
ATTRIBUTES
r60
no change, since guard is
false
r100
r90
r125
SEE ALSO
signed
0x12330030
0x80007fff
0x12330030
0x7fff8000
Result
15
dspalu
–1..–2
1, 3
No
71
—
0
2
2
A-28
15
]