Zilog Z86193 Manual do Utilizador descarregar pdf (Página 247)

CPU

User Manual

UM001604-0108 Instruction Description

240

Swap Nibbles

Syntax

SWAP dst

Instruction Format

Operation

dst(7-4) ↔ dst(3-0)

The contents of the lower four bits and upper four bits of the destination operand are

swapped.

Address modes R or IR can be used to specify a 4-bit Working Register. In this format, des-

tination Working Register operand is specified by adding

1110b (Eh) to the high nibble of

the operand. For example, if Working Register

R12 (CH) is the destination operand, then

ECh is used as the destination operand in the Op Code.

Example 1

If Register BCh contains B3h (10110011B), the statement:

SWAP B3h

Op Code: F0 B3

leaves the value 3Bh (00111011B) in Register BCh. The Z and S Flags are cleared.

Cycles

OPC

(Hex)

Address Mode

dst

OPC dst

6F0 R

6F1 IR

Flag Description

C Unaffected

Z Set if the result is zero; cleared otherwise.

S Set if the result bit 7 is set; cleared otherwise.

V Undefined

D Unaffected

H Unaffected

Edst

Note:

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Zilog Z86193 Manual do Utilizador Página 247