;ports
#define PORT_ADD_LOW 02h
#define PORT_ADD_HIGH 03h
#define PORT_COMMAND 04h
#define PORT_TIMER_FREQ_LOW 05h
#define PORT_TIMER_FREQ_HIGH 06h

;for commands for PORT_COMMAND
#define COMMAND_WRITE_SERIEL 01h
#define COMMAND_ENABLE_TIMER 02h
#define COMMAND_DISABLE_TIMER 03h
#define COMMAND_NMI_ACK 04h

#define INTURUPT_CAUESE_ADDRESS 77 ;temp
#define INTURUPT_CAUES_TIMER 0x01

#define output(x, y) ld a,y \ out (x),a
#define command(x) output(PORT_COMMAND, x)



.org 0
 ld sp,stack
 im 1
 ei
 output(PORT_ADD_LOW, testfoo & FFh)
 output(PORT_ADD_HIGH, testfoo >> 8)
 command(COMMAND_WRITE_SERIEL)
 output(PORT_ADD_LOW, output & FFh)
 output(PORT_ADD_HIGH, output >> 8)
 output(PORT_TIMER_FREQ_LOW, 88h)
 output(PORT_TIMER_FREQ_HIGH, 10h)
 command(COMMAND_ENABLE_TIMER)
 jr $
 ;leave a bit of space for SP
.db 0,0
.db 0,0
.db 0,0
.db 0,0
stack:
.db 0,0

.align 0038h
inturupt:
.if $ != 0038h
.fail "& should be 38h"
.endif
 di
 command(COMMAND_NMI_ACK)
 command(COMMAND_WRITE_SERIEL)
 ei
 ret

output:
 .db "int",0
testfoo:
 .db "test",0