Zilog Z80380 Manual do Utilizador descarregar pdf (Página 193)

5-159

Z380

™

USER'S MANUAL

ZILOG

DC-8297-03

SBC

SUBTRACT WITH CARRY (BYTE)

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

Operation: A ← A - src - C

The source operand together with the Carry flag 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: SBC A,R 10011-r- 2

RX: SBC A,RX 11y11101 1001110w 2

IM: SBC A,n 11011110 ——n— 2

IR: SBC A,(HL) 10011110 2+r

X: SBC A,(XY+d) 11y11101 10011110 ——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

1 2 ... 188 189 190 191 192 193 194 195 196 197 198 ... 267 268

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Zilog Z80380 Manual do Utilizador Página 193