Character codes: Difference between revisions
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→{{header|68000 Assembly}}: Added explanation of "UnpackNibbles8" and "PrintChar"
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=={{header|68000 Assembly}}==
The printing routine only understands ASCII characters as codes anyway, so the "given a code produce its character" part is trivial.
PrintChar routine is omitted for brevity. It converts the two Cursor variables to a FIX layer address and outputs the character using the NEOGEO's FIX layer. Characters are stored in ROM and arranged in ASCII order.
<lang 68000devpac> JSR ResetCoords ;RESET TYPING CURSOR
Line 120 ⟶ 121:
ADDQ.B #1,D1
DBRA D2,PrintAllTheCodes
rts
UnpackNibbles8:
; INPUT: D0 = THE VALUE YOU WISH TO UNPACK.
; HIGH NIBBLE IN HIGH WORD OF D0, LOW NIBBLE IN LOW WORD. SWAP D0 TO GET THE OTHER HALF.
pushWord D1
CLR.W D1
MOVE.B D0,D1
CLR.L D0
MOVE.B D1,D0 ;now D0 = D1 = $000000II, where I = input
AND.B #$F0,D0 ;chop off bottom nibble
LSR.B #4,D0 ;downshift top nibble into bottom nibble of the word
SWAP D0 ;store in high word
AND.B #$0F,D1 ;chop off bottom nibble
MOVE.B D1,D0 ;store in low word
popWord D1
rts</lang>
Output can be seen [https://ibb.co/ngtDXpq here.]
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