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INSTRUCTION SET S3CC11B/FC11B SBC (1) – Subtract with Carry Register Format: SBC Rn, Ri Description: The SBC (Subtract with Carry) instruction is used to synthesize 32-bit subtraction. If register pairs R0, R1 and R2, R3 hold 32-bit values (R0 and R2 hold the least-significant word), the following instructions leave the 32-bit result in R0, R1: SUB R0, R2 SBC R1, R3 SBC subtracts the value of register Ri, and the value of the Carry flag (stored in the T bit), from the value of register Rn, and stores the result in register Rn. The T bit and the V flag are updated based on the result. Operation: 15 14 13 12 1 0 0 0 11 8 Rn Rn := Rn + ~Ri + T bit T bit := Carry from (Rn + ~Ri + T bit) V flag := Overflow from (Rn + ~Ri + T bit) if(Rn == R6/R7) Z0/Z1 := ((Rn + ~Ri + T) == 0) Exceptions: None Notes: None 6-92 7 6 5 4 0 0 1 1 3 0 Ri
