Assembly: 

SB rt, offset(rs)

nanoMIPS

Store Byte

Purpose:

Store Byte.

Store byte from register $rt to memory address $rs + offset (register plus

immediate).

Availability:

nanoMIPS

Format:

SB[U12]

100001

rt

rs

0001

u

6

5

5

4

12 

offset = u

SB[16]

010111

rtz3

rs3

01

u

6

3

3

2

2 

rt = decode_gpr(rtz3, 'gpr3.src.store')
rs = decode_gpr(rs3, 'gpr3')
offset = u

SB[GP]

010001

rt

001

u

6

5

3

18 

rs = 28
offset = u

SB[S9]

101001

rt

rs

s[8]

0001

0

00

s[7:0]

6

5

5

1

4

1

2

8 

offset = sign_extend(s, from_nbits=9)

Operation: 

va = effective_address(GPR[rs], offset, 'Store')
data = zero_extend(GPR[rt], from_nbits=8)
write_memory_at_va(data, va, nbytes=1)

Exceptions:

Address Error. Bus Error. TLB Invalid. TLB Modified. TLB Refill. Watch.