NEC PD750004 User Manual page 75

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.
RAMC0:
RAMC1:
Note Data memory locations at 000H to 003H are allocated to general registers XA and HL, so these are
not cleared.
SET1 MBE
SEL MB0
MOV XA,#00H
MOV HL,#04H
MOV @HL,A
INCS L
BR RAMC0
INCS H
BR RAMC0
SEL MB1
MOV @HL,A
INCS L
BR RAMC1
INCS H
CHAPTER 4 INTERNAL CPU FUNCTIONS
Note
; Clear 04H to FFH
; L <– L + 1
; H <– H + 1
; Clear 100H to 1FFH
; L <– L + 1
; H <– H + 1
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