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SISDIGIT.Z80
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2000-06-30
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34 lines
;
; SYSLIB Module Name: SISDIGIT
; Author: Richard Conn
; SYSLIB Version Number: 3.6
; Module Version Number: 1.1
public isdigit
;
; ISDIGIT returns Zero Flag Set if char in A is numeric (0-9).
; ISDIGIT returns NZ if not.
;
; Char in A is unaffected.
;
ISDIGIT:
PUSH BC ; SAVE BC
LD C,A ; SAVE CHAR IN C
AND 7FH ; MASK OUT MSB
CP '0' ; LESS THAN 0?
JP C,NO
CP '9'+1 ; LESS THAN OR EQUAL TO 9?
JP NC,NO
XOR A ; SET FLAG
LD A,C ; GET CHAR
POP BC ; RESTORE BC
RET
NO:
LD A,0FFH ; SET FLAG
OR A
LD A,C ; GET CHAR
POP BC ; RESTORE BC
RET
END