Philips Semiconductors
DSPCPU Operations for TM1100
File: ops.fm5, modified 7/23/99
PRELIMINARY INFORMATION
A-129
32-bit load with displacement
SYNTAX
[ IF r
guard ] ld32d(d) rsrc1
→ rdest
FUNCTION
if r
guard then {
if PCSW.bytesex = LITTLE_ENDIAN then
bs
← 3
else
bs
← 0
r
dest<7:0>
← mem[rsrc1 + d + (3 ⊕ bs)]
r
dest<15:8>
← mem[rsrc1 + d + (2 ⊕ bs)]
r
dest<23:16>
← mem[rsrc1 + d + (1 ⊕ bs)]
r
dest<31:24>
← mem[rsrc1 + d + (0 ⊕ bs)]
}
ATTRIBUTES
Function unit
dmem
Operation code
7
Number of operands
1
Modier
7 bits
Modier range
–256..252 by 4
Latency
3
Issue slots
4, 5
DESCRIPTION
The ld32d operation loads the 32-bit memory value from the address computed by r
src1 + d and stores the result
in r
dest. The d value is an opcode modier, must be in the range –256 to 252 inclusive, and must be a multiple of 4. If
the memory address computed by r
src1 + d is not a multiple of 4, the result of ld32d is undened 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 ld32d operation can be used to access the MMIO address aperture (the result of MMIO access by 8- or 16-bit
memory operations is undened). The state of the BSX bit in the PCSW has no effect on MMIO access by ld32d.
The ld32d operation optionally takes a guard, specied in r
guard. If a guard is present, its LSB controls the
modication of the destination register and the occurrence of side effects. If the LSB of r
guard is 1, rdest is written and
the data cache status bits are updated if the addressed locations are cacheable. if the LSB of r
guard is 0, rdest is not
changed and ld32d has no side effects whatever.
EXAMPLES
Initial Values
Operation
Result
r10 = 0xcfc,
[0xd00] = 0x84, [0xd01] = 0x33,
[0xd02] = 0x22, [0xd03] = 0x11
ld32d(4) r10
→ r60
r60
← 0x84332211
r30 = 0, r20 = 0xd0c,
[0xd04] = 0x48, [0xd05] = 0x66,
[0xd06] = 0x55, [0xd07] = 0x44
IF r30 ld32d(-8) r20
→ r70
no change, since guard is false
r40 = 1, r20 = 0xd0c,
[0xd04] = 0x48, [0xd05] = 0x66,
[0xd06] = 0x55, [0xd07] = 0x44
IF r40 ld32d(-8) r20
→ r80
r80
← 0x48665544
r50 = 0xd01
ld32d(-8) r50
→ r90
r90 undened, since 0xd01 +(–8) is not a
multiple of 4
SEE ALSO
ld32d