Zilog Z8F0130 - Manual (Page 251)

eZ8
™
CPU Core
User Manual
UM012820-0810 SUBX Instruction
236
Attributes
Escaped Mode Addressing
Using Escaped Mode Addressing, address mode ER for the source or des-
tination specifies 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 234h contains the value 2Eh , and Register 912h contains the
value 1Bh , the following statement leaves the value 13h in Register
234h , sets the D flag, and clears the C, Z, S, V, and H flags:
SUBX 234h, 912h

Object Code: 28 91 22 34
If Register 56Ch contains the value 2Ah , the following statement leaves
the value 27h in Register 56Ch , sets the D flag, and clears the C, Z, S, V,
and H flags:
SUBX 56Ch, #03h

Object Code: 29 03 05 6C
Mnemonic
Destination,
Source
Op
Code
(Hex)
Operand 1 Operand 2 Operand 3
SUBX ER1, ER2 28 ER2[11:4] {ER2[3:0],
ER1[11:8]} ER1[7:0]
SUBX ER1, IM 29 IM {0h,
ER1[11:8]} ER1[7:0]