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Zilog Z8F0130 User Manual

Page 93

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eZ8

CPU Core

User Manual

UM012820-0810

ADCX Instruction

78

Attributes

Escaped Mode Addressing

Using Escaped Mode Addressing, address mode ER for the source or des-
tination can specify a working register with 4-bit addressing.

If the high byte of the source or destination address is

EEh

(

11101110b

),

a working register is inferred. For example, the operand

EE3h

selects

Working Register R3. The full 12-bit address is provided by

{RP[3:0],RP[7:4], 3h}

.

To access registers on Page

Eh

(addresses

E00h

to

EFFh

), set the Page

Pointer, RP[3:0], to

Eh

and set the Working Group Pointer,

RP[7:4]

, to

the preferred Working Group.

Sample Usage

If Register

634h

contains the value

2Eh

, the Carry flag is set, and Regis-

ter

B12h

contains the value

1bh

, the following statement leaves the value

4Ah

in Register

634h

, sets the H flag, and clears the C, Z, S, V, and D

flags:

ADCX 634h, B12h

Object Code: 18 B1 26 34

Using Escaped Mode Addressing, if Working Register R4 contains the
value

2Eh

, the Carry flag is set, and Register

B12h

contains the value

1bh

, the following statement leaves the value

4Ah

in Working Register

R4, sets the H flag, and clears the C, Z, S, V, and D flags:

Mnemonic

Destination,
Source

Op
Code
(Hex)

Operand 1

Operand 2 Operand 3

ADCX

ER1, ER2

18

ER2[11:4]

{ER2[3:0],
ER1[11:8]}

ER1[7:0]

ADCX

ER1, IM

19

IM

{0h,
ER1[11:8]}

ER1[7:0]