Rev. 1.50, 10/04, page 242 of 448
10.1.22 EXTU (Extend as Unsigned): Arithmetic Instruction
Format
Operation
Instruction Code
Cycle
T Bit
EXTU.B Rm,Rn
Rm zero-extended from
byte
→
Rn
0110nnnnmmmm1100
1
—
EXTU.W Rm,Rn
Rm zero-extended from
word
→
Rn
0110nnnnmmmm1101
1
—
Description:
This instruction zero-extends the contents of general register Rm and stores the
result in Rn.
For a byte specification, 0 is transferred to Rn bits 8 to 31. For a word specification, 0 is
transferred to Rn bits 16 to 31.
Notes:
None
Operation:
EXTUB(long m, long n)
/* EXTU.B Rm,Rn */
{
R[n] = R[m];
R[n] &= 0x000000FF;
PC += 2;
}
EXTUW(long m, long n)
/* EXTU.W Rm,Rn */
{
R[n] = R[m];
R[n] &= 0x0000FFFF;
PC += 2;
}
Example:
EXTU.B R0,R1
;
Before execution
R0 = H'FFFFFF80
;
After execution
R1 = H'00000080
EXTU.W R0,R1
;
Before execution R0 = H'FFFF8000
;
After execution
R1 = H'00008000
Summary of Contents for SuperH SH-4A
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