Rev. 1.50, 10/04, page 287 of 448
10.1.44 NEGC (Negate with Carry): Arithmetic Instruction
Format
Operation
Instruction Code
Cycle
T Bit
NEGC Rm,Rn
0 – Rm – T
→
Rn,
borrow
→
T
0110nnnnmmmm1010
1 Borrow
Description:
This instruction subtracts the contents of general register Rm and the T bit from 0
and stores the result in Rn. A borrow resulting from the operation is reflected in the T bit. The
NEGC instruction is used for sign inversion of a value exceeding 32 bits.
Notes:
None
Operation:
NEGC(long m, long n) /* NEGC Rm,Rn */
{
unsigned long temp;
temp = 0-R[m];
R[n] = temp-T;
if (0<temp) T = 1;
else T = 0;
if (temp<R[n]) T = 1;
PC += 2;
}
Example:
CLRT
;
Sign inversion of R0:R1 (64 bits)
NEGC
R1,R1
;
Before execution R1 = H'00000001, T = 0
;
After execution
R1 = H'FFFFFFFF, T = 1
NEGC
R0,R0
;
Before execution R0 = H'00000000, T = 1
;
After execution
R0 = H'FFFFFFFF, T = 1
Summary of Contents for SuperH SH-4A
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