Zilog Z80380 - Manual (Page 38)

I/O ADDRESS SPACES C-Compiler Overview
2–4 UM004001-COR1103
A CCCESING I/O A DDRESS S PACE
The Z380 instruction set does not allow indirect acess of the internal I/O address space
through a register.
To acess the I/O adress space use the on-chip peripheral-addresses as operands to the
IN0/OUT0 machine instructions. Variable pointers can not be used to access the internal I/O
address space and address constants must be used.
The recommended usage the I/O adress space is hown in the below example.
typedef volatile unsigned char __INTIO *PBINTIO;
#defineIO_ADDR((PBINTIO)0x0002)
// …
unsigned char ch;
// …
IO_ADDR[0] = ch;// store to I/O address 2
// …
ch = IO_ADDR[0];// load from I/O address 2
// …