/*
 * Testing inline assembler with HI-TECH C under CP/M
 * Make rotation effects on four Z80 PIO's
 */

#include <stdio.h>

#define LEDS		00H			/* Digital I/O board */

#define PIO1_A_D	068H		/* Z80 PIO #1 */
#define PIO1_A_C	06AH
#define PIO1_B_D	069H
#define PIO1_B_C	06BH

#define PIO2_A_D	06CH		/* Z80 PIO #2 */
#define PIO2_A_C	06EH
#define PIO2_B_D	06DH
#define PIO2_B_C	06FH

#define PIO3_A_D	0F0H		/* Z80 PIO #3 */
#define PIO3_A_C	0F2H
#define PIO3_B_D	0F1H
#define PIO3_B_C	0F3H

#define PIO4_A_D	0F4H		/* Z80 PIO #4 */
#define PIO4_A_C	0F6H
#define PIO4_B_D	0F5H
#define PIO4_B_C	0F7H

	/* Forward declarations */
	void delay(long);
	void pio1(int);
	void pio2(int);
	void pio3(int);
	void pio4(int);
	

/* Entry point to program */
int main()
{
	printf("Hello RC2014, Z80 CPU + four Z80 PIO's !\n");

	/* Set SC103 - Z80 PIO's to output mode */
#asm

		PUSH AF
		
		LD A, 0FH				; Control word for PIO, set output mode
		OUT (PIO1_A_C), A		; PIO #1 port A
		OUT (PIO1_B_C), A		; PIO #1 port B
		OUT (PIO2_A_C), A		; PIO #2 port A
		OUT (PIO2_B_C), A		; PIO #2 port B
		OUT (PIO3_A_C), A		; PIO #3 port A
		OUT (PIO3_B_C), A		; PIO #3 port B
		OUT (PIO4_A_C), A		; PIO #4 port A
		OUT (PIO4_B_C), A		; PIO #4 port B
		
		; Turn all LED's OFF
		XOR A					; LD A, 0 -> XOR A
		OUT (LEDS), A
		OUT (PIO1_A_D), A
		OUT (PIO1_B_D), A
		OUT (PIO2_A_D), A
		OUT (PIO2_B_D), A
		OUT (PIO3_A_D), A
		OUT (PIO3_B_D), A
		OUT (PIO4_A_D), A
		OUT (PIO4_B_D), A
	
		POP AF
#endasm

	pio1(5);
	pio2(5);
	pio3(5);
	pio4(5);
	
	printf("Finished\n");
	return 0;
}

void pio1(int count)
{
	int i;
	for (i = 0; i < count; i++)
	{
#asm
		PUSH AF
		PUSH BC
		PUSH DE
		
		LD D, 10000000B
		LD E, 00000001B
		
		; Display initial state
		LD A, E
		OUT (PIO1_A_D), A
		LD A, D
		OUT (PIO1_B_D), A
		
		LD A, 10000000B
		OUT (LEDS), A
		CALL ASMDELAY
		
		LD B, 07H			; 8 LED's = 7 rotation cycles

REPEAT1:
		; Read PIO #1 to DE
		IN A, (PIO1_A_D) 
		LD E, A
		IN A, (PIO1_B_D) 
		LD D, A
			
		;
		; 8-bit rotation in D and E
		;

		SCF				; The Carry Flag in the flags register is set
		RL E			; Rotate E left, bit 7 goes to Carry Flag and CF to bit 0  
		
		SCF				; The Carry Flag in the flags register is set
		RR D			; Rotate D right, Carry Flag with E(b7) goes to bit 7, D(b0) goes to CF
			
		; Write DE back to PIO #1
		LD A, E
		OUT (PIO1_A_D), A
		LD A, D
		OUT (PIO1_B_D), A
		
		CALL ASMDELAY
		
		DJNZ REPEAT1
		
		POP DE
		POP BC
		POP AF
#endasm
	
		delay(500l);
	}
}

void pio2(int count)
{
	int i;

#asm
	LD A, 01000000B
	OUT (LEDS), A
	CALL ASMDELAY
#endasm

	for (i = 0; i < count; i++)
	{
#asm
		PUSH AF
		PUSH DE
			
		LD B, 08H			; 8 shift cycles
		LD DE, 0001H
		LD A, 10000000B
		
REPEAT2a:
		RLC A
    
	;
	; 16-bit left shift in DE
	;
		; Write DE back to PIO #2
		PUSH AF
		LD A, E
		OUT (PIO2_A_D), A
		LD A, D
		OUT (PIO2_B_D), A
		POP AF
		CALL ASMDELAY
		
		SLA E				; Shift E left, bit 7 goes to Carry Flag bit 0 is reset	

		DJNZ REPEAT2a		; Loop through 8 cycles

		RL D				; Push Carry Flag to D bit 0
		LD B, 08H	

		CALL ASMDELAY
		
REPEAT2b:
		RLC A

		; Write DE back to PIO #2
		PUSH AF
		LD A, E
		OUT (PIO2_A_D), A
		LD A, D
		OUT (PIO2_B_D), A
		POP AF
		CALL ASMDELAY
		
		SLA D				; Shift D left, bit 7 goes to Carry Flag bit 0 is reset

		DJNZ REPEAT2b		; Loop through 8 cycles
			
		POP DE
		POP AF
#endasm
	
		delay(150l);
	}
}

void pio3(int count)
{
	int i;
	
#asm
	PUSH AF
	
	LD A, 00100000B
	OUT (LEDS), A
	POP AF
	
	CALL ASMDELAY
#endasm	
	
	for (i = 0; i < count; i++)
	{
#asm
		PUSH AF
		PUSH DE
		PUSH BC

REPEAT3a:
		LD B, 08H			; 8 shift cycles
		LD DE, 0001H
		
REPEAT3b:	
    
	;
	; 16-bit left shift in DE
	;
		; Write DE back to PIO #3
		LD A, D
		OUT (PIO3_A_D), A
		LD A, E
		OUT (PIO3_B_D), A
		
		CALL ASMDELAY

		SLA E				; Shift E left, bit 7 goes to Carry Flag bit 0 is reset	

		DJNZ REPEAT3b		; Loop through 8 cycles

		RL D				; Push Carry Flag to D bit 0
		LD B, 08H			; 8 shift cycles

REPEAT3c:

		; Write DE back to PIO #3
		LD A, D
		OUT (PIO3_A_D), A
		LD A, E
		OUT (PIO3_B_D), A
		
		CALL ASMDELAY

		SLA D				; Shift D left, bit 7 goes to Carry Flag bit 0 is reset

		DJNZ REPEAT3c		; Loop through 8 cycles

		POP BC
		POP DE
		POP AF
#endasm
	}

	delay(120l);
}

void pio4(int count)
{
	int i;
	
#asm
	LD A, 00010000B
	OUT (LEDS), A
	CALL ASMDELAY
#endasm		
	
	for (i = 0; i < count; i++)
	{
#asm
		PUSH AF
		PUSH BC
		
		LD B, 0FFH
		LD A, 0
		OUT (PIO4_A_D), A
PIO3R:	
		CALL ASMDELAY
		
		; Read PIO #4 A to A
		IN A, (PIO4_A_D) 
		INC A
		; Write DE back to PIO #4
		OUT (PIO4_A_D), A
		
		DJNZ PIO3R
			
		POP BC
		POP AF
#endasm
	}

	delay(200l);
}


#asm

	;
	; ASM Routine to add a delay 
	;
ASMDELAY:
        PUSH BC
		
		LD C, 08FH
DELAY1: LD B, 0FFH
DELAY2:	NOP
       	DJNZ DELAY2
        DEC C
        JR NZ, DELAY1
        
		POP BC
        RET
#endasm

/* C function to add a delay */
void delay(long duration)
{
	long i;
	for (i = 0; i < duration; i++)
	{	
		;
#asm			
		NOP
#endasm	
	}
}