1.1 --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
     1.2 +++ b/README	Fri Feb 23 13:29:37 2018 +0200
     1.3 @@ -0,0 +1,27 @@
     1.4 +Amiga floppy boot test
     1.5 +----------------------
     1.6 +Bootblock code in src/boot/boot.s uses the Amiga exec in ROM to load the
     1.7 +flat binary image from from the first N sectors to address 0x10000, and jumps
     1.8 +there. The size of the binary is patched immediately before the first
     1.9 +instruction of the boot code by tools/mk_adf.py.
    1.10 +
    1.11 +Linkscript puts code from the .startup segment (src/startup.s) at the load
    1.12 +address, and it starts by setting the trap0 exception vector to point to the
    1.13 +next instruction and executes a trap 0, to enter supervisor mode and take
    1.14 +complete control of the system. Then it clears .bss, sets the stack and calls
    1.15 +the C main function.
    1.16 +
    1.17 +A few words about the graphics hack
    1.18 +-----------------------------------
    1.19 +The IFS fractal is calculated in 16.16 fixed point, using a mersenne twister
    1.20 +random number generator (src/rng.c) for picking an IFS transformation to do each
    1.21 +time. Two bitplanes are enabled both pointing to the same IFS pixel buffer, with
    1.22 +a few scanlines offset and a different per-pixel scroll (data fetch delay) in
    1.23 +BPLCON1. The palette is set up in a way to give priority to bitplane 0, i.e. use
    1.24 +green for pixels with bit 0 set, and use a shadow color for pixels which have
    1.25 +only bit 1 set. This gives the illusion of a shadow layer.
    1.26 +
    1.27 +Serial debug output
    1.28 +-------------------
    1.29 +Serial comm needs RTS/CTS (hardware) flow control.
    1.30 +  stty 38400 crtscts cs8 -parenb -ixon -ixoff raw -iutf8 -F /dev/ttyUSB0

     2.1 --- a/src/hwregs.h	Thu Feb 22 14:46:32 2018 +0200
     2.2 +++ b/src/hwregs.h	Fri Feb 23 13:29:37 2018 +0200
     2.3 @@ -345,6 +345,10 @@
     2.4  #define REG_COPJMP1		REG(REGN_COPJMP1)
     2.5  #define REG_COPJMP2		REG(REGN_COPJMP2)
     2.6  
     2.7 +#define REG_SERPER		REG(REGN_SERPER)
     2.8 +#define REG_SERDATR		REG(REGN_SERDATR)
     2.9 +#define REG_SERDAT		REG(REGN_SERDAT)
    2.10 +
    2.11  /* ------ bits ------- */
    2.12  #define SETBITS(x)	((x) | 0x8000)
    2.13  #define CLRBITS(x)	(x)
    2.14 @@ -425,4 +429,16 @@
    2.15  #define CIAA_PA_FIR0	0x40
    2.16  #define CIAA_PA_FIR1	0x80
    2.17  
    2.18 +enum {
    2.19 +	SERDATR_STOP8	= 0x0100,
    2.20 +	SERDATR_STOP9	= 0x0200,
    2.21 +	SERDATR_RXD		= 0x0800,
    2.22 +	SERDATR_TSRE	= 0x1000,
    2.23 +	SERDATR_TBE		= 0x2000,
    2.24 +	SERDATR_RBF		= 0x4000,
    2.25 +	SERDATR_OVRUN	= 0x8000
    2.26 +};
    2.27 +
    2.28 +#define ADKCON_UARTBRK	0x0800
    2.29 +
    2.30  #endif	/* HWREGS_H_ */

     3.1 --- a/src/main.c	Thu Feb 22 14:46:32 2018 +0200
     3.2 +++ b/src/main.c	Fri Feb 23 13:29:37 2018 +0200
     3.3 @@ -2,9 +2,14 @@
     3.4  #include "intr.h"
     3.5  #include "copper.h"
     3.6  #include "rng.h"
     3.7 +#include "serial.h"
     3.8  
     3.9 -#define BPLSZ  (320 / 8 * 256)
    3.10 -static unsigned char fb0[BPLSZ];
    3.11 +#define SCR_W	336
    3.12 +#define SCR_H	256
    3.13 +#define HMOD	((SCR_W - 320) / 8)
    3.14 +
    3.15 +#define BPLSZ  (SCR_W / 8 * SCR_H)
    3.16 +static unsigned char fb0[BPLSZ + 3 * SCR_W];
    3.17  
    3.18  extern uint16_t dbgval;
    3.19  
    3.20 @@ -29,8 +34,7 @@
    3.21  		: "a0", "d0")
    3.22  
    3.23  static uint32_t coplist[] = {
    3.24 -	COPPER_MOVE(REGN_BPL1PTH, 0),
    3.25 -	COPPER_MOVE(REGN_BPL1PTL, 0),
    3.26 +	0, 0, 0, 0,	/* placeholder of bitplane pointer setting */
    3.27  
    3.28  	COPPER_MOVE(REGN_COLOR0, 0x234),
    3.29  	COPPER_VWAIT(15),
    3.30 @@ -52,22 +56,31 @@
    3.31  {
    3.32  	int32_t x = 0, y = 0;
    3.33  
    3.34 +	ser_init(38400);
    3.35 +	ser_print("Amiga debug console initialized\n");
    3.36 +
    3.37  	REG_INTENA = SETBITS(INTEN_VERTB | INTEN_MASTER);
    3.38  
    3.39  	REG_DMACON = CLRBITS(DMA_ALL);
    3.40 -	REG_BPLCON0 = BPLCON0_COUNT(1) | BPLCON0_COLOR;
    3.41 -	REG_BPLCON1 = 0;
    3.42 +	REG_BPLCON0 = BPLCON0_COUNT(2) | BPLCON0_COLOR;
    3.43 +	REG_BPLCON1 = 0xfa;
    3.44 +	REG_BPL1MOD = HMOD - 2;
    3.45 +	REG_BPL2MOD = HMOD - 2;
    3.46  	REG_DIWSTART = 0x2981;
    3.47  	REG_DIWSTOP = 0x29c1;
    3.48 -	REG_DDFSTART = 0x38;
    3.49 +	REG_DDFSTART = 0x30;
    3.50  	REG_DDFSTOP = 0xd0;
    3.51  
    3.52  	REG_COLOR0 = 0x235;
    3.53 -	REG_COLOR1 = 0x2f5;
    3.54 +	REG_COLOR1 = 0x2e5;
    3.55 +	REG_COLOR2 = 0x113;
    3.56 +	REG_COLOR3 = 0x2e5;
    3.57  
    3.58  	wait_vblank();
    3.59 -	coplist[0] = COPPER_MOVE(REGN_BPL1PTH, (uint32_t)fb0 >> 16);
    3.60 -	coplist[1] = COPPER_MOVE(REGN_BPL1PTL, (uint32_t)fb0);
    3.61 +	coplist[0] = COPPER_MOVE(REGN_BPL1PTH, ((uint32_t)fb0 + 3 * SCR_W / 8) >> 16);
    3.62 +	coplist[1] = COPPER_MOVE(REGN_BPL1PTL, (uint32_t)fb0 + 3 * SCR_W / 8);
    3.63 +	coplist[2] = COPPER_MOVE(REGN_BPL2PTH, (uint32_t)fb0 >> 16);
    3.64 +	coplist[3] = COPPER_MOVE(REGN_BPL2PTL, (uint32_t)fb0);
    3.65  	REG32_COP1LC = (uint32_t)coplist;
    3.66  	REG_COPJMP1 = 0;
    3.67  
    3.68 @@ -105,11 +118,15 @@
    3.69  		py = 128 - (x >> 11);
    3.70  
    3.71  		if(py >= 0) {
    3.72 -			pptr = fb0 + (py * 320 + px) / 8;
    3.73 +			pptr = fb0 + (py * SCR_W + px) / 8;
    3.74  			*pptr = *pptr | (0x80 >> (px & 7));
    3.75  		}
    3.76  
    3.77 -		wait_vblank();
    3.78 +		if((REG_CIAA_PORTA & CIAA_PA_FIR0) == 0) {
    3.79 +			ser_print("restarting fractal\n");
    3.80 +			wait_vblank();
    3.81 +			clear_bpl(fb0);
    3.82 +		}
    3.83  	}
    3.84  
    3.85  	return 0;

     4.1 --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
     4.2 +++ b/src/serial.c	Fri Feb 23 13:29:37 2018 +0200
     4.3 @@ -0,0 +1,48 @@
     4.4 +#include "hwregs.h"
     4.5 +#include "serial.h"
     4.6 +
     4.7 +#define CLK		3546895
     4.8 +#define BVAL(b)	(CLK / (b) - 1)
     4.9 +
    4.10 +static inline uint16_t baudval(int baud)
    4.11 +{
    4.12 +	switch(baud) {
    4.13 +	case 110: return BVAL(110);
    4.14 +	case 300: return BVAL(300);
    4.15 +	case 600: return BVAL(600);
    4.16 +	case 1200: return BVAL(1200);
    4.17 +	case 2400: return BVAL(2400);
    4.18 +	case 4800: return BVAL(4800);
    4.19 +	case 9600: return BVAL(9600);
    4.20 +	case 14400: return BVAL(14400);
    4.21 +	case 19200: return BVAL(19200);
    4.22 +	case 38400: return BVAL(38400);
    4.23 +	case 57600: return BVAL(57600);
    4.24 +	case 115200: return BVAL(115200);
    4.25 +	default:
    4.26 +		break;
    4.27 +	}
    4.28 +	return BVAL(baud);
    4.29 +}
    4.30 +
    4.31 +void ser_init(int baud)
    4.32 +{
    4.33 +	REG_SERPER = baudval(baud) & 0x7fff;
    4.34 +}
    4.35 +
    4.36 +/*
    4.37 +void ser_putchar(int c)
    4.38 +{
    4.39 +	REG_SERDAT = ((uint16_t)c & 0xff) | 0x100;
    4.40 +}
    4.41 +*/
    4.42 +
    4.43 +void ser_print(const char *s)
    4.44 +{
    4.45 +	while(*s) {
    4.46 +		if(*s == '\n') {
    4.47 +			ser_putchar('\r');
    4.48 +		}
    4.49 +		ser_putchar(*s++);
    4.50 +	}
    4.51 +}

     5.1 --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
     5.2 +++ b/src/serial.h	Fri Feb 23 13:29:37 2018 +0200
     5.3 @@ -0,0 +1,21 @@
     5.4 +#ifndef SERIAL_H_
     5.5 +#define SERIAL_H_
     5.6 +
     5.7 +#include "hwregs.h"
     5.8 +
     5.9 +/* dff030 is REG_SERDAT
    5.10 + * dff018 is REG_SERDATR
    5.11 + * bit 13 of SERDATR is TBE (transmit buffer empty)
    5.12 + */
    5.13 +#define ser_putchar(c) \
    5.14 +	asm volatile( \
    5.15 +		"or.w #0x100, %0\n\t" \
    5.16 +		"0: btst #13, 0xdff018\n\t" \
    5.17 +		"beq 0b\n\t" \
    5.18 +		"move.w %0, 0xdff030\n\t" \
    5.19 +		:: "d"((int16_t)c))
    5.20 +
    5.21 +void ser_init(int baud);
    5.22 +void ser_print(const char *s);
    5.23 +
    5.24 +#endif	/* SERIAL_H_ */