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Nonextended Address
Extended Address
Figure 4-8. Formation of Extended and Nonextended Addresses
4.5.2.1
Using Extended Instructions
The code example below illustrates the use of extended instructions to access data in page 01H.
EP_REG
EQU 1FE5H
RSEG AT 1CH
TEMP:
DSW 1
RESULT:
DSW 1
CSEG AT 0FF2080H
.
.
.
SUBB:
PUSHA
LD
EST
ADD
EST
.
.
.
POPA
RET
.
.
.
DONE:
BR DONE
END
From EP_REG
23
16 15
From CPU
23
16 15
TEMP,#1234H
TEMP,010600H
RESULT,TEMP,#4000H
RESULT,010602H
16-bit Data Address Register
16-bit Data Address Register
;SOME CODE
;
;
;save flags, disable interrupts
;
;store temp value in 010600H
;do something with registers
;store result in 010602H
;more eld/est instructions
;
;
;restore flags and interrupts
;
;more code
;
;
MEMORY PARTITIONS
0
0
A2514-01
4-25
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