tm1300 NXP Semiconductors, tm1300 Datasheet - Page 312

• Manufacturer Part Number: tm1300
• Description: Tm-1300 Media Processor
• Manufacturer: NXP Semiconductors

TM1300 Data Book
dspidualmul
SYNTAX
FUNCTION
DESCRIPTION
pairs of high and low 16-bit halfwords of r src1 and r src2 . Both products are clipped into the range [2
[0x7fff..0x8000]) and written into the corresponding halfwords of r dest . All values are signed 16-bit integers.
modification of the destination register. If the LSB of r guard is 1, r dest is written; otherwise, r dest is not changed.
EXAMPLES
A-26
r30 = 0x0020010, r40 = 0x00030020
r10 = 0, r30 = 0x0020010, r40 = 0x00030020
r20 = 1, r30 = 0x0020010, r40 = 0x00030020
r50 = 0x80000002, r80 = 0x00024000
r110 = 0x08000003, r120 = 0x00108001
As shown below, the
The
[ IF r guard ] dspidualmul r src1 r src2
if r guard then {
}
32-bit signed products
r src1
temp1
temp2
if temp1 < 0xffff8000 then temp1
if temp2 < 0xffff8000 then temp2
if temp1 > 0x7fff then temp1
if temp2 > 0x7fff then temp2
r dest <31:16>
r dest <15:0>
Two full-precision
dspidualmul
3
3
sign_ext16to32(r src1 <15:0>)
sign_ext16to32(r src1 <31:16>)
Initial Values
signed
temp1<15:0>
temp2<15:0>
dspidualmul
operation optionally takes a guard, specified in r guard . If a guard is present, its LSB controls the
PRODUCT SPECIFICATION
Clip to [2
1
r dest
signed
0x7fff
0x7fff
15
–1..–2
0x8000
0x8000
3
signed
operation computes two 16-bit clipped, signed products separately on the two
Dual clipped multiply of signed 16-bit halfwords
15
sign_ext16to32(r src2 <15:0>)
dspidualmul r30 r40
IF r10 dspidualmul r30 r40
IF r20 dspidualmul r30 r40
dspidualmul r50 r80
dspidualmul r110 r120
sign_ext16to32(r src2 <31:16>)
]
signed
0
0
r dest
1
Operation
3
r src2
3
signed
r60
r90
signed
r125
Clip to [2
signed
0
r70
r100
Function unit
Operation code
Number of operands
Modifier
Modifier range
Latency
Issue slots
15
dspidualabs dspidualadd
–1..–2
dspidualsub dspiabs
Philips Semiconductors
15
1
r60
no change, since guard is false
r100
r90
r125
]
ATTRIBUTES
SEE ALSO
0x00060200
0x80007fff
0x00060200
0x7fff8000
signed
Result
15
–1..–2
0
dspmul
2, 3
No
95
—
0
2
3
15
] (or