Zilog Z8F0130 - Manual (Page 317)

UM013037-1212 Automatic Working Register Definitions
Zilog Developer Studio II – Z8 Encore!
User Manual
293

ld a, 1<<2 | 1<<2 | 1<<1


The constant expression in the preceding instruction evaluates to 2A H.


If you want to perform the Shift Left operations before the OR operation, use parentheses
as:


ld a, #(1<<2)|(1<<2)|(1<<1)


The modified constant expression evaluates to
6 H .
Automatic Working Register Definitions
Z8 Encore! supports 4-, 8-, and 12-bit addressing of registers. Automatic working register
definitions allow you to specify which mode the assembler uses. The default is 12-bit
mode.
The following examples show how to use automatic working register definitions:
lab equ %54

ldx @r1,@.ER(lab) is encoded as 8754E1

ldx @.ER(lab),@r2 is encoded as 97E254
ldx rp, #.WRG(wbase)
If wbase is at %234 , it is then equivalent to:
ldx rp, #%32
ld r0,.R(reg)
If reg is at %43 , it is then equivalent to:
ld r0, r3
.ER Indicates that the enclosed address is to be encoded as a 8-bit register pair
address. Only valid in ldx instruction.
.R Indicates that the lower nibble of the enclosed label has to be encoded in the
instruction.
.RR Indicates that the enclosed label is at the even boundary and the lower nibble is
to be encoded in the instruction.
.WRG Computes the value to store in the RP register so that the given label can be
accessed using the 4- or 8-bit addressing mode.