Example of graphic drawing by gdc, Mz3500 – Sharp MZ-3500 User Manual
Page 44
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MZ3500
(Subroutine lo send command and parameter to the GDC
via the FIFO)
HL reg — First address of the command code oarameter table.
B. reg — Q'ty of data.
C reg ^ 60H (graphic GDC), 70H (character GDC)
N
>
FIFO Empty?
OUTl
; COMMAND — GDC
RET
Example of graphic drawing by GDC
1) Dot display
VRAM
16-bit
structure
Example to display a dot on the fourth bit of the address
CSRW
C
49H
- COMMAND CODE
PI
01H
— Low order one byte
of the
ab
solute address
P2
ООН
— High order one byte
of The ab
solute address
P3
ЗОН
— Dot address (dAD)
WRITE
C
23H
- COMMAND CODE
VECTE
C
6CH
- COMMAND CODE
49 -
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