Zilog Z80380 Bedienungsanleitung PDF herunterladen (Seite 206)

5-172

Z380

™

USER'S MANUAL

DC-8297-03

ZILOG

SUB

SUBTRACT (BYTE)

SUB A,src src = R, RX, IM, IR, X

Operation: A ← A - src

The source operand is subtracted from the accumulator and the difference is stored in the

accumulator. The contents of the source are unaffected. Two's complement subtraction is

performed.

Flags: S: Set if the result is negative; cleared otherwise

Z: Set if the result is zero; cleared otherwise

H: Set if there is a borrow from bit 4 of the result; cleared otherwise

V: Set if arithmetic overflow occurs, that is, if the operands are of different signs and the

result is of the same sign as the source; cleared otherwise

N: Set

C: Set if there is a borrow from the most significant bit of the result; cleared otherwise

Addressing Execute

Mode Syntax Instruction Format Time Note

R: SUB A,R 10010-r- 2

RX: SUB A,RX 11y11101 1001010w 2

IM: SUB A,n 11010110 ——n— 2

IR: SUB A,(HL) 10010110 2+r

X: SUB A,(XY+d) 11y11101 10010110 ——d— 4+r I

Field Encodings: r: per convention

y: 0 for IX, 1 for IY

w: 0 for high byte, 1 for low byte

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Zilog Z80380 Bedienungsanleitung Seite 206