Encoding:

POOL32A

000000

rt

rs

rd

0

ADDWC

1111000101

6

5

5

5

1

10

SPECIAL3

011111

rs

rt

rd

ADDWC

10001

ADDU.QB

010000

6

5

5

5

5

6

Format: 

ADDWC rd, rs, rt

microMIPSDSP

Add Word with Carry Bit

Purpose:

Add Word with Carry Bit

Add two signed 32-bit values with the carry bit in the DSPControl register.

Description: 

rd = sign_extend(rs + rt + DSPControlc:13)

The right-most 32-bit value in register rt is added to the right-most 32-bit value in register rs and the carry bit in the

DSPControl register. The result is then sign-extended to 64 bits and written to destination register rd.

If the addition results in either overflow or underflow, this instruction writes a 1 t o bit 20 in the ouflag field of the

DSPControl register.

Restrictions:

No data-dependent exceptions are possible.

Operation: 

temp32..0 = ( GPR[rs]31 || GPR[rs]31..0 ) + ( GPR[rt]31 || GPR[rt]31..0 ) + ( 032 || DSPControlc:13 )
if ( temp32 != temp31 ) then
   DSPControlouflag:20 = 1
endif
GPR[rd]63..0 = (temp31)32 || temp31..0

Exceptions:

Reserved Instruction, DSP Disabled