Zilog Z80380 Instrukcja Użytkownika Pobierz pdf (Strona 212)

5-178

Z380

™

USER'S MANUAL

DC-8297-03

ZILOG

TSTIO

TEST I/O PORT

TSTIO src src = IM

Operation: (C) AND src

A logical AND operation is performed between the corresponding bits of the source and the

contents of the I/O location. The contents of both the I/O location and the source are

unaffected; only the flags are modified as a result of this instruction. No external I/O

transaction will be generated as a result of this instruction, although the I/O address will

appear on the adress bus while the internal read is occurring. The peripheral address in the

C register is placed on the low byte of the address bus and zeros are placed on all other

address lines.

Flags: S: Set if the most significant bit of the result is set; cleared otherwise

Z: Set if all bits of the result are zero; cleared otherwise

H: Set

P: Set if the parity is even; cleared otherwise

N: Cleared

C: Cleared

Addressing Execute

Mode Syntax Instruction Format Time Note

TSTIO n 11101101 01110100 ——n— 3+i

1 2 ... 207 208 209 210 211 212 213 214 215 216 217 ... 267 268

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