Nintendo Ultra64 Programmer's Manual page 230

SW
31
SW
1 0 1 0 1 1
6
Format:
sw rt, offset(base)
Description:
The 16-bit
DMEM address. The contents of general register
the DMEM address.
Since DMEM is only 4K bytes, only the lower 12 bits of the effective address are used.
Operation:
T:
Exceptions:
None
230
Store Word
26 25 21 20
base
5
offset
is sign-extended and added to the contents of general register

16
Addr ((offset ) || offset
15
data  GPR
31...0
StoreDMEM (WORD, data, Addr
16 15
rt
5
rt
are stored at the DMEM location specified by
) + GPR[base]
15...0
)
11...0
SW
offset
16
base
0
to form a