
Philips Semiconductors
DSPCPU Operations for TM1300
PRODUCT SPECIFICATION
A-189
Unsigned 16-bit load with index
SYNTAX
[ IF rguard ] uld16r rsrc1 rsrc2
→
rdest
FUNCTION
if
rguard
then {
if
PCSW.bytesex = LITTLE_ENDIAN
then
bs
←
1
else
bs
←
0
temp<7:0>
←
mem[rsrc1+ rsrc2+ (1
⊕
bs)]
temp<15:8>
←
mem[rsrc1+ rsrc2+ (0
⊕
bs)]
rdest
←
zero_ext16to32(temp<15:0>)
}
ATTRIBUTES
Function unit
Operation code
Number of operands
Modifier
Modifier range
Latency
Issue slots
dmem
198
2
No
—
3
4, 5
DESCRIPTION
The
uld16r
operation loads the 16-bit memory value from the address computed by rsrc1 + rsrc2 zero extends it
to 32 bits, and writes the result in rdest If the memory address computed by rsrc1 + rsrc2 is not a multiple of 2, the
result of
uld16r
is undefined but no exception will be raised. This load operation is performed as little-endian or big-
endian depending on the current setting of the bytesex bit in the PCSW.
The result of an access by
uld16r
to the MMIO address aperture is undefined; access to the MMIO aperture is
defined only for 32-bit loads and stores.
The
uld16r
operation optionally takes a guard, specified in rguard If a guard is present, its LSB controls the
modification of the destination register and the occurrence of side effects. If the LSB of rguardis 1, rdestis written and
the data cache status bits are updated if the addressed locations are cacheable. if the LSB of rguard is 0, rdest is not
changed and
uld16r
has no side effects whatever.
EXAMPLES
Initial Values
Operation
Result
r10 = 0xd00, r20 = 2, [0xd02] = 0x22,
[0xd03] = 0x11
r50 = 0, r40 = 0xd04, r30 = 0xfffffffc,
[0xd00] = 0x84, [0xd01] = 0x33
r60 = 1, r40 = 0xd04, r30 = 0xfffffffc,
[0xd00] = 0x84, [0xd01] = 0x33
r70 = 0xd01, r30 = 0xfffffffc
uld16r r10 r20
→
r80
r80
←
0x00002211
IF r50 uld16r r40 r30
→
r90
no change, since guard is false
IF r60 uld16r r40 r30
→
r100
r100
←
0x00008433
uld16r r70 r30
→
r110
r110 undefined (0xd01 +(–4) is not a multiple
of 2)
SEE ALSO
uld16 ild16 uld16d ild16d
ild16r uld16x ild16x
uld16r