
TM1300 Data Book
Philips Semiconductors
A-188
PRODUCT SPECIFICATION
Unsigned 16-bit load with displacement
SYNTAX
[ IF rguard ] uld16d(d) rsrc1
→
rdest
FUNCTION
if
rguard
then {
if
PCSW.bytesex = LITTLE_ENDIAN
then
bs
←
1
else
bs
←
0
temp<7:0>
←
mem[rsrc1+ d+ (1
⊕
bs)]
temp<15:8>
←
mem[rsrc1+ d+ (0
⊕
bs)]
rdest
←
zero_ext16to32(temp<15:0>)
}
ATTRIBUTES
Function unit
Operation code
Number of operands
Modifier
Modifier range
Latency
Issue slots
dmem
197
1
7 bits
–128..126 by 2
3
4, 5
DESCRIPTION
The
uld16d
operation loads the 16-bit memory value from the address computed by rsrc1+ d zero extends it to 32
bits, and writes the result in rdest The d value is an opcode modifier, must be in the range –128 and 126 inclusive,
and must be a multiple of 2. If the memory address computed by rsrc1 + d is not a multiple of 2, the result of
uld16d
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
uld16d
to the MMIO address aperture is undefined; access to the MMIO aperture is
defined only for 32-bit loads and stores.
The
uld16d
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
uld16d
has no side effects whatever.
EXAMPLES
Initial Values
Operation
Result
r10 = 0xd00, [0xd02] = 0x22,
[0xd03] = 0x11
r30 = 0, r20 = 0xd04, [0xd00] = 0x84,
[0xd01] = 0x33
r40 = 1, r20 = 0xd04, [0xd00] = 0x84,
[0xd01] = 0x33
r50 = 0xd01
uld16d(2) r10
→
r60
r60
←
0x00002211
IF r30 uld16d(-4) r20
→
r70
no change, since guard is false
IF r40 uld16d(-4) r20
→
r80
r80
←
0x00008433
uld16d(-4) r50
→
r90
r90 undefined (0xd01 +(–4) is not a multiple
of 2)
SEE ALSO
uld16 ild16 ild16d uld16r
ild16r uld16x ild16x
uld16d