ZiLOG Z80 Handbook page 231

INPUT OUTPUT
ASXBIN
(HL)
8 ASCII
ASXHEX
(HL)
ASXBCD
(HL)
BINARY CHARACTERS
2 ASCII
HEX CHARACTERS
I
7
8-BIT BINARY
0
1
A
(HL)
I
8-B IT B I NARY A
7
(HL)
7
I
0
0
A
BCD DIGITl 1113 D DIGIT 21
2 ASCII
BCD CHARACTERS
ASXDEC
(HL)
7 0
H
L
F
16-BIT BINARY
5 ASCII
DECIMAL CHARACTERS (IX)
Fig. 16 -1. ASCII to base X conversions.
The second routine of this group converts an 8-bit binary value in
the C register to two ASCII hexadecimal digits. On entry, HL points
to the buffer area and on exit, HL points to buffer + 2.
BXASH LD A,FOH MASK
AND A,C GET FIRST CHARACTER
RRCA
RRCA
RRCA
RRCA ALIGN FOR CONVERT
CALL CVERT CONVERT
LD A,FH MASK
AND A,C GET SECOND CHARACTER
CALL CVERT CONVERT
RET RETURN
CVERT ADD A,30H CONVERT TO 0-15
CP A,10
JP M,JUMP1 GO IF 0-9
ADD A,7 CONVERT 10-15 TO A-F
JUMP1 LD (HL),A STORE IN BUFFER
INC HL BUMP POINTER
RET RETURN
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