Sharp mz-3500 Manual For Use page 265

Section B:
Hardware interface
B.2. Calling Hardware Functions
All calls of hardware functions are done using
Eos
calling this system function, the following data are
CPU registers:
function
50.
When
to be passed in the
Register
c:
32H
Register DE: Pointer to a table of this kind:
DB FUNC
Hardware function code
DB AREG
Data fo< register
A
ow
BCREG
Data fo< register pair BC
ow
DE REG
Data fo< register pair DE
ow
HLREG
Data fo< register pair HL
Prior to calling the specified hardware driver function, EOS loads the
CPU registers with the data from the parameter table. All results are
returned in register pair HL. As a convenience, the contents of register
L are copied into register A, too. Function 25 (Move Memory Block)
represents an exception to this rule, as it returns all register pairs
BC, DE, and HL with changed contents.
Let us assume
bypassing EOS.
this:
LD
LD
CALL
REGSET: DB
DB
DW
OW
ow
You want to display a character on the screen
directly,
Then, You would have to write a piece of code similar to
C,50"
EOS function code
DE,REGSET Register settings
5
Execution
4 Hardware function code
~
A
register
CHAR
Character to be displayed
in
BC
~
DE register
~
HL register
EOS System manual
Daeumling & Zimmermann
Page 127