NEC PD750008 User Manual
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CHAPTER 4 INTERNAL CPU FUNCTIONS
Data memory is undefined when it is reset. For this reason, it is to be initialized to zero (RAM clear) usually
at the start of a program. Remember to perform this initialization. Otherwise, unexpected bugs may occur.
Example The following program clears data at addresses 000H to 1FFH in RAM.
SET1
MBE
SEL
MB0
MOV
XA,#00H
MOV
HL,#04H
RAMC0:
MOV
@HL,A
; Clear 04H to FFH
Note
INCS
L
; L <– L + 1
BR
RAMC0
INCS
H
; H <– H + 1
BR
RAMC0
SEL
MB1
RAMC1:
MOV
@HL,A
; Clear 100H to 1FFH
INCS
L
; L <– L + 1
BR
RAMC1
INCS
H
; H <– H + 1
Note Data memory locations at 000H to 003H are allocated to general registers XA and HL, so these are
not cleared.