PNX1300 Datasheet, PDF (507/548 Pages) NXP Semiconductors – Media Processors

PNX1300/01/02/11 Data Book
zex16
SYNTAX
[ IF rguard ] zex16 rsrc1 → rdest
FUNCTION
if rguard then
rdest ← zero_ext16to32(rsrc1<15:0>)
Philips Semiconductors
Zero extend 16 bits
pseudo-op for pack16lsb
ATTRIBUTES
Function unit
Operation code
Number of operands
Modifier
Modifier range
Latency
Issue slots
alu
53
1
No
—
1
1, 2, 3, 4, 5
SEE ALSO
sex16 sex8 zex8
DESCRIPTION
The zex16 operation is a pseudo operation transformed by the scheduler into a pack16lsb with 0 as the first
argument and rsrc1 as the second. (Note: pseudo operations cannot be used in assembly source files.)
As shown below, the zex16 operation zero extends the least-significant 16-bit halfword of the argument, r src1, to
32 bits and writes the result in rdest.
31
rsrc1
15
0
unsigned
31
15
0
rdest 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
unsigned
The zex16 operation optionally takes a guard, specified in rguard. If a guard is present, its LSB controls the
modification of the destination register. If the LSB of rguard is 1, rdest is written; otherwise, rdest is not changed.
EXAMPLES
Initial Values
r30 = 0xffff0040
r10 = 0, r40 = 0xff0fff91
r20 = 1, r40 = 0xff0fff91
r50 = 0x00000091
Operation
zex16 r30 → r60
IF r10 zex16 r40 → r70
IF r20 zex16 r40 → r100
zex16 r50 → r110
Result
r60 ← 0x00000040
no change, since guard is false
r100 ← 0x0000ff91
r110 ← 0x00000091
A-209
PRELIMINARYSPECIFICATION