SBWC Instruction

Integer OVerflow

Purpose:

To perform extended-precision subtraction

Format:

opcode sub.rl, dif.ml

Operation:

dif <- dif - sub - C;

Condition
Codes:

N <- dif LSS 0;
Z <- dif EQL 0;
V <- {integer overflow};
C <- {borrow from the most significant bit};

Exceptions:

Opcodes:

SBWC

Subtract with carry

Description:

The subtrahend operand and the contents of the C condition code bit are subtracted from the difference operand and the difference operand is replaced by the result.

Notes:

1.: On overflow, the difference operand is replaced by the low order bits of the true result.
2.: The two subtraction operations are performed simultaneously.