PNX1300 Datasheet, PDF (417/548 Pages) NXP Semiconductors – Media Processors

PNX1300/01/02/11 Data Book
ineg
SYNTAX
[ IF rguard ] ineg rsrc1 → rdest
FUNCTION
if rguard then
rdest ← –rsrc1
Philips Semiconductors
Signed negate
pseudo-op for isub
ATTRIBUTES
Function unit
Operation code
Number of operands
Modifier
Modifier range
Latency
Issue slots
alu
13
1
No
—
1
1, 2, 3, 4, 5
SEE ALSO
isub
DESCRIPTION
The ineg operation is a pseudo operation transformed by the scheduler into an isub with r0 (always contains 0)
as the first argument and rsrc1 as the second argument. (Note: pseudo operations cannot be used in assembly source
files.)
The ineg operation computes the negative of rsrc1 and writes the result into rdest. The argument is a signed
integer; the result is an unsigned integer. If rsrc1 = 0x80000000, then ineg returns 0x80000000 since the positive
value is not representable.
The ineg 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 = 0xffffffff
r10 = 0, r40 = 0xfffffff4
r20 = 1, r40 = 0xfffffff4
r50 = 0x80000001
r60 = 0x80000000
r20 = 1
Operation
ineg r30 → r60
IF r10 ineg r40 → r80
IF r20 ineg r40 → r90
ineg r50 → r100
ineg r60 → r110
ineg r20 → r120
Result
r60 ← 0x00000001
no change, since guard is false
r90 ← 0xc
r100 ← 0x7fffffff
r110 ← 0x80000000
r120 ← 0xffffffff
A-119
PRELIMINARYSPECIFICATION