Hello,
I needed a Port I/O routine for the Z80 that would accept the address as a
parameter, so I wrote 2 functions with inline ASM to do it. I would have used
sfr, but the addresses need to be passed as a parameter (ie. I can't just
#define or hardcode them).
I'm pretty new to ASM, and with all the warning in the manual about
protecting the registers I just wanted to check with some experienced people to
see if these functions looked OK. They do work fine under emulation, haven't
tried them on real hardware.
//these 2 are outside of the functions so the symbols will be seen by the ASM
code
static uint8 io_val;
static uint8 io_addr;
uint8 io_read(uint8 addr) {
io_addr = addr;
_asm
push af
push bc
ld bc, (_io_addr)
in a, (c)
ld (_io_val), a
pop bc
pop af
_endasm;
return io_val;
}
void io_write(uint8 addr, uint8 val) {
io_addr = addr;
io_val = val;
_asm
push af
push bc
ld a,(_io_val)
ld bc,(_io_addr)
out (c),a
pop bc
pop af
_endasm;
}
Best regards,
Indy Sams
mailto:[email protected]
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