2
2-12 M32R-FPU Software Manual (Rev.1.01)

2.2 Instruction format

There are two major instruction formats: two 16-bit instructions packed together within a

word boundary, and a single 32-bit instruction (see Figure 2.2.1). Figure 2.2.2 shows

the instruction format of M32R CPU.

Fig. 2.2.2 Instruction format of M32R CPU
Fig. 2.2.1 16-bit instruction and 32-bit instruction
< 16-bit instruction >
op1 R
1
R
2
op2
op1 R
1
c
op1 cond c
op1 R
1
R
2
op2 c
op1 R
1
R
2
op2 c
op1 R
1
c
op1 cond c
< 32-bit instruction >
R
1
= R
1
op R
2
R
1
= R
1
op c
Branch (Short Displacement)
R
1
= R
1
op c
Branch
Compare and Branch
R
1
= R
2
op c
op1 R
s
0000
op2 op3 R
d
0000
op4
op1 R
s1
R
s2
op2
Floating-point 2-operand
(Rd=op(Rs))
Floating-point 3-operand
(Rd=Rs1 op Rs2)
op3 R
d
0000
op4
16-bit instruction A
+ 0 + 1 + 2 + 3
1 word
32-bit instruction
address
1 word
+ 0 + 1 + 2 + 3address
16-bit instruction B
INSTRUCTION SET

2.2 Instruction format