/* This file is part of SIS (SPARC instruction simulator)

   Copyright (C) 1995-2022 Free Software Foundation, Inc.
   Contributed by Jiri Gaisler, European Space Agency

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 3 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */

/* The control space devices */

/* This must come before any other includes.  */
#include "defs.h"

#include <sys/types.h>
#include <stdio.h>
#include <string.h>
#ifdef HAVE_TERMIOS_H
#include <termios.h>
#endif
#include <sys/fcntl.h>
#include <sys/file.h>
#include <unistd.h>
#include "sis.h"
#include "sim-config.h"

extern int      ctrl_c;
extern int32_t    sis_verbose;
extern int32_t    sparclite, sparclite_board;
extern int      rom8,wrp,uben;
extern char     uart_dev1[], uart_dev2[];

int dumbio = 0; /* normal, smart, terminal oriented IO by default */

/* MEC registers */
#define MEC_START 	0x01f80000
#define MEC_END 	0x01f80100

/* Memory exception waitstates */
#define MEM_EX_WS 	1

/* ERC32 always adds one waitstate during RAM std */
#define STD_WS 1

#ifdef ERRINJ
extern int errmec;
#endif

#define MEC_WS	0		/* Waitstates per MEC access (0 ws) */
#define MOK	0

/* MEC register addresses */

#define MEC_MCR		0x000
#define MEC_SFR  	0x004
#define MEC_PWDR  	0x008
#define MEC_MEMCFG	0x010
#define MEC_IOCR	0x014
#define MEC_WCR		0x018

#define MEC_MAR0  	0x020
#define MEC_MAR1  	0x024

#define MEC_SSA1 	0x020
#define MEC_SEA1 	0x024
#define MEC_SSA2 	0x028
#define MEC_SEA2 	0x02C
#define MEC_ISR		0x044
#define MEC_IPR		0x048
#define MEC_IMR 	0x04C
#define MEC_ICR 	0x050
#define MEC_IFR 	0x054
#define MEC_WDOG  	0x060
#define MEC_TRAPD  	0x064
#define MEC_RTC_COUNTER	0x080
#define MEC_RTC_RELOAD	0x080
#define MEC_RTC_SCALER	0x084
#define MEC_GPT_COUNTER	0x088
#define MEC_GPT_RELOAD	0x088
#define MEC_GPT_SCALER	0x08C
#define MEC_TIMER_CTRL	0x098
#define MEC_SFSR	0x0A0
#define MEC_FFAR	0x0A4
#define MEC_ERSR	0x0B0
#define MEC_DBG		0x0C0
#define MEC_TCR		0x0D0

#define MEC_BRK		0x0C4
#define MEC_WPR		0x0C8

#define MEC_UARTA	0x0E0
#define MEC_UARTB	0x0E4
#define MEC_UART_CTRL	0x0E8
#define SIM_LOAD	0x0F0

/* Memory exception causes */
#define PROT_EXC	0x3
#define UIMP_ACC	0x4
#define MEC_ACC		0x6
#define WATCH_EXC	0xa
#define BREAK_EXC	0xb

/* Size of UART buffers (bytes) */
#define UARTBUF	1024

/* Number of simulator ticks between flushing the UARTS. 	 */
/* For good performance, keep above 1000			 */
#define UART_FLUSH_TIME	  3000

/* MEC timer control register bits */
#define TCR_GACR 1
#define TCR_GACL 2
#define TCR_GASE 4
#define TCR_GASL 8
#define TCR_TCRCR 0x100
#define TCR_TCRCL 0x200
#define TCR_TCRSE 0x400
#define TCR_TCRSL 0x800

/* New uart defines */
#define UART_TX_TIME	1000
#define UART_RX_TIME	1000
#define UARTA_DR	0x1
#define UARTA_SRE	0x2
#define UARTA_HRE	0x4
#define UARTA_OR	0x40
#define UARTA_CLR	0x80
#define UARTB_DR	0x10000
#define UARTB_SRE	0x20000
#define UARTB_HRE	0x40000
#define UARTB_OR	0x400000
#define UARTB_CLR	0x800000

#define UART_DR		0x100
#define UART_TSE	0x200
#define UART_THE	0x400

/* MEC registers */

static char     fname[256];
static int32_t    find = 0;
static uint32_t   mec_ssa[2];	/* Write protection start address */
static uint32_t   mec_sea[2];	/* Write protection end address */
static uint32_t   mec_wpr[2];	/* Write protection control fields */
static uint32_t   mec_sfsr;
static uint32_t   mec_ffar;
static uint32_t   mec_ipr;
static uint32_t   mec_imr;
static uint32_t   mec_isr;
static uint32_t   mec_icr;
static uint32_t   mec_ifr;
static uint32_t   mec_mcr;	/* MEC control register */
static uint32_t   mec_memcfg;	/* Memory control register */
static uint32_t   mec_wcr;	/* MEC waitstate register */
static uint32_t   mec_iocr;	/* MEC IO control register */
static uint32_t   posted_irq;
static uint32_t   mec_ersr;	/* MEC error and status register */
static uint32_t   mec_tcr;	/* MEC test comtrol register */

static uint32_t   rtc_counter;
static uint32_t   rtc_reload;
static uint32_t   rtc_scaler;
static uint32_t   rtc_scaler_start;
static uint32_t   rtc_enabled;
static uint32_t   rtc_cr;
static uint32_t   rtc_se;

static uint32_t   gpt_counter;
static uint32_t   gpt_reload;
static uint32_t   gpt_scaler;
static uint32_t   gpt_scaler_start;
static uint32_t   gpt_enabled;
static uint32_t   gpt_cr;
static uint32_t   gpt_se;

static uint32_t   wdog_scaler;
static uint32_t   wdog_counter;
static uint32_t   wdog_rst_delay;
static uint32_t   wdog_rston;

enum wdog_type {
    init, disabled, enabled, stopped
};

static enum wdog_type wdog_status;


/* ROM size 1024 Kbyte */
#define ROM_SZ	 	0x100000
#define ROM_MASK 	0x0fffff

/* RAM size 4 Mbyte */
#define RAM_START 	0x02000000
#define RAM_END 	0x02400000
#define RAM_MASK 	0x003fffff

/* SPARClite boards all seem to have RAM at the same place. */
#define RAM_START_SLITE	0x40000000
#define RAM_END_SLITE 	0x40400000
#define RAM_MASK_SLITE 	0x003fffff

/* Memory support variables */

static uint32_t   mem_ramr_ws;	/* RAM read waitstates */
static uint32_t   mem_ramw_ws;	/* RAM write waitstates */
static uint32_t   mem_romr_ws;	/* ROM read waitstates */
static uint32_t   mem_romw_ws;	/* ROM write waitstates */
static uint32_t	mem_ramstart;	/* RAM start */
static uint32_t	mem_ramend;	/* RAM end */
static uint32_t	mem_rammask;	/* RAM address mask */
static uint32_t   mem_ramsz;	/* RAM size */
static uint32_t   mem_romsz;	/* ROM size */
static uint32_t   mem_accprot;	/* RAM write protection enabled */
static uint32_t   mem_blockprot;	/* RAM block write protection enabled */

static unsigned char	romb[ROM_SZ];
static unsigned char	ramb[RAM_END - RAM_START];


/* UART support variables */

static int32_t    fd1, fd2;	/* file descriptor for input file */
static int32_t    Ucontrol;	/* UART status register */
static unsigned char aq[UARTBUF], bq[UARTBUF];
static int32_t    anum, aind = 0;
static int32_t    bnum, bind = 0;
static char     wbufa[UARTBUF], wbufb[UARTBUF];
static unsigned wnuma;
static unsigned wnumb;
static FILE    *f1in, *f1out, *f2in, *f2out;
#ifdef HAVE_TERMIOS_H
static struct termios ioc1, ioc2, iocold1, iocold2;
#endif
static int      f1open = 0, f2open = 0;

static char     uarta_sreg, uarta_hreg, uartb_sreg, uartb_hreg;
static uint32_t   uart_stat_reg;
static uint32_t   uarta_data, uartb_data;

#ifdef ERA
int era = 0;
int erareg;
#endif

/* Forward declarations */

static void	decode_ersr (void);
#ifdef ERRINJ
static void	iucomperr (void);
#endif
static void	mecparerror (void);
static void	decode_memcfg (void);
static void	decode_wcr (void);
static void	decode_mcr (void);
static void	close_port (void);
static void	mec_reset (void);
static void	mec_intack (int32_t level);
static void	chk_irq (void);
static void	mec_irq (int32_t level);
static void	set_sfsr (uint32_t fault, uint32_t addr,
			  uint32_t asi, uint32_t read);
static int32_t	mec_read (uint32_t addr, uint32_t asi, uint32_t *data);
static int	mec_write (uint32_t addr, uint32_t data);
static void	port_init (void);
static uint32_t	read_uart (uint32_t addr);
static void	write_uart (uint32_t addr, uint32_t data);
static void	flush_uart (void);
static void	uarta_tx (void);
static void	uartb_tx (void);
static void	uart_rx (void *arg);
static void	uart_intr (void *arg);
static void	uart_irq_start (void);
static void	wdog_intr (void *arg);
static void	wdog_start (void);
static void	rtc_intr (void *arg);
static void	rtc_start (void);
static uint32_t	rtc_counter_read (void);
static void	rtc_scaler_set (uint32_t val);
static void	rtc_reload_set (uint32_t val);
static void	gpt_intr (void *arg);
static void	gpt_start (void);
static uint32_t	gpt_counter_read (void);
static void	gpt_scaler_set (uint32_t val);
static void	gpt_reload_set (uint32_t val);
static void	timer_ctrl (uint32_t val);
static void *	get_mem_ptr (uint32_t addr, uint32_t size);
static void	store_bytes (unsigned char *mem, uint32_t waddr,
			uint32_t *data, int sz, int32_t *ws);

extern int	ext_irl;


/* One-time init */

void
init_sim(void)
{
    port_init();
}

/* Power-on reset init */

void
reset(void)
{
    mec_reset();
    uart_irq_start();
    wdog_start();
}

static void
decode_ersr(void)
{
    if (mec_ersr & 0x01) {
	if (!(mec_mcr & 0x20)) {
	    if (mec_mcr & 0x40) {
	        sys_reset();
	        mec_ersr = 0x8000;
	        if (sis_verbose)
	            printf("Error manager reset - IU in error mode\n");
	    } else {
	        sys_halt();
	        mec_ersr |= 0x2000;
	        if (sis_verbose)
	            printf("Error manager halt - IU in error mode\n");
	    }
	} else
	    mec_irq(1);
    }
    if (mec_ersr & 0x04) {
	if (!(mec_mcr & 0x200)) {
	    if (mec_mcr & 0x400) {
	        sys_reset();
	        mec_ersr = 0x8000;
	        if (sis_verbose)
	            printf("Error manager reset - IU comparison error\n");
	    } else {
	        sys_halt();
	        mec_ersr |= 0x2000;
	        if (sis_verbose)
	            printf("Error manager halt - IU comparison error\n");
	    }
	} else
	    mec_irq(1);
    }
    if (mec_ersr & 0x20) { 
	if (!(mec_mcr & 0x2000)) {
	    if (mec_mcr & 0x4000) {
	        sys_reset();
	        mec_ersr = 0x8000;
	        if (sis_verbose)
	            printf("Error manager reset - MEC hardware error\n");
	    } else {
	        sys_halt();
	        mec_ersr |= 0x2000;
	        if (sis_verbose)
	            printf("Error manager halt - MEC hardware error\n");
	    }
	} else
	    mec_irq(1);
    }
}

#ifdef ERRINJ
static void
iucomperr()
{
    mec_ersr |= 0x04;
    decode_ersr();
}
#endif

static void
mecparerror(void)
{
    mec_ersr |= 0x20;
    decode_ersr();
}


/* IU error mode manager */

void
error_mode(uint32_t pc)
{

    mec_ersr |= 0x1;
    decode_ersr();
}


/* Check memory settings */

static void
decode_memcfg(void)
{
    if (rom8) mec_memcfg &= ~0x20000;
    else mec_memcfg |= 0x20000;

    mem_ramsz = (256 * 1024) << ((mec_memcfg >> 10) & 7);
    mem_romsz = (128 * 1024) << ((mec_memcfg >> 18) & 7);

    if (sparclite_board) {
	mem_ramstart = RAM_START_SLITE;
	mem_ramend = RAM_END_SLITE;
	mem_rammask = RAM_MASK_SLITE;
    }
    else {
	mem_ramstart = RAM_START;
	mem_ramend = RAM_END;
	mem_rammask = RAM_MASK;
    }
    if (sis_verbose)
	printf("RAM start: 0x%x, RAM size: %d K, ROM size: %d K\n",
	       mem_ramstart, mem_ramsz >> 10, mem_romsz >> 10);
}

static void
decode_wcr(void)
{
    mem_ramr_ws = mec_wcr & 3;
    mem_ramw_ws = (mec_wcr >> 2) & 3;
    mem_romr_ws = (mec_wcr >> 4) & 0x0f;
    if (rom8) {
    	if (mem_romr_ws > 0 )  mem_romr_ws--;
	mem_romr_ws = 5 + (4*mem_romr_ws);
    }
    mem_romw_ws = (mec_wcr >> 8) & 0x0f;
    if (sis_verbose)
	printf("Waitstates = RAM read: %d, RAM write: %d, ROM read: %d, ROM write: %d\n",
	       mem_ramr_ws, mem_ramw_ws, mem_romr_ws, mem_romw_ws);
}

static void
decode_mcr(void)
{
    mem_accprot = (mec_wpr[0] | mec_wpr[1]);
    mem_blockprot = (mec_mcr >> 3) & 1;
    if (sis_verbose && mem_accprot)
	printf("Memory block write protection enabled\n");
    if (mec_mcr & 0x08000) {
	mec_ersr |= 0x20;
	decode_ersr();
    }
    if (sis_verbose && (mec_mcr & 2))
	printf("Software reset enabled\n");
    if (sis_verbose && (mec_mcr & 1))
	printf("Power-down mode enabled\n");
}

/* Flush ports when simulator stops */

void
sim_halt(void)
{
#ifdef FAST_UART
    flush_uart();
#endif
}

int
sim_stop(SIM_DESC sd)
{
  ctrl_c = 1;
  return 1;
}

static void
close_port(void)
{
    if (f1open && f1in != stdin)
	fclose(f1in);
    if (f2open && f2in != stdin)
	fclose(f2in);
}

void
exit_sim(void)
{
    close_port();
}

static void
mec_reset(void)
{
    int             i;

    find = 0;
    for (i = 0; i < 2; i++)
	mec_ssa[i] = mec_sea[i] = mec_wpr[i] = 0;
    mec_mcr = 0x01350014;
    mec_iocr = 0;
    mec_sfsr = 0x078;
    mec_ffar = 0;
    mec_ipr = 0;
    mec_imr = 0x7ffe;
    mec_isr = 0;
    mec_icr = 0;
    mec_ifr = 0;
    mec_memcfg = 0x10000;
    mec_wcr = -1;
    mec_ersr = 0;		/* MEC error and status register */
    mec_tcr = 0;		/* MEC test comtrol register */

    decode_memcfg();
    decode_wcr();
    decode_mcr();

    posted_irq = 0;
    wnuma = wnumb = 0;
    anum = aind = bnum = bind = 0;

    uart_stat_reg = UARTA_SRE | UARTA_HRE | UARTB_SRE | UARTB_HRE;
    uarta_data = uartb_data = UART_THE | UART_TSE;

    rtc_counter = 0xffffffff;
    rtc_reload = 0xffffffff;
    rtc_scaler = 0xff;
    rtc_enabled = 0;
    rtc_cr = 0;
    rtc_se = 0;

    gpt_counter = 0xffffffff;
    gpt_reload = 0xffffffff;
    gpt_scaler = 0xffff;
    gpt_enabled = 0;
    gpt_cr = 0;
    gpt_se = 0;

    wdog_scaler = 255;
    wdog_rst_delay = 255;
    wdog_counter = 0xffff;
    wdog_rston = 0;
    wdog_status = init;

#ifdef ERA
    erareg = 0;
#endif

}


static void
mec_intack(int32_t level)
{
    int             irq_test;

    if (sis_verbose)
	printf("interrupt %d acknowledged\n", level);
    irq_test = mec_tcr & 0x80000;
    if ((irq_test) && (mec_ifr & (1 << level)))
	mec_ifr &= ~(1 << level);
    else
	mec_ipr &= ~(1 << level);
   chk_irq();
}

static void
chk_irq(void)
{
    int32_t           i;
    uint32_t          itmp;
    int		    old_irl;

    old_irl = ext_irl;
    if (mec_tcr & 0x80000) itmp = mec_ifr;
    else itmp  = 0;
    itmp = ((mec_ipr | itmp) & ~mec_imr) & 0x0fffe;
    ext_irl = 0;
    if (itmp != 0) {
	for (i = 15; i > 0; i--) {
	    if (((itmp >> i) & 1) != 0) {
		if ((sis_verbose) && (i > old_irl)) 
		    printf("IU irl: %d\n", i);
		ext_irl = i;
	        set_int(i, mec_intack, i);
		break;
	    }
	}
    }
}

static void
mec_irq(int32_t level)
{
    mec_ipr |= (1 << level);
    chk_irq();
}

static void
set_sfsr(uint32_t fault, uint32_t addr, uint32_t asi, uint32_t read)
{
    if ((asi == 0xa) || (asi == 0xb)) {
	mec_ffar = addr;
	mec_sfsr = (fault << 3) | (!read << 15);
	mec_sfsr |= ((mec_sfsr & 1) ^ 1) | (mec_sfsr & 1);
	switch (asi) {
	case 0xa:
	    mec_sfsr |= 0x0004;
	    break;
	case 0xb:
	    mec_sfsr |= 0x1004;
	    break;
	}
    }
}

static int32_t
mec_read(uint32_t addr, uint32_t asi, uint32_t *data)
{

    switch (addr & 0x0ff) {

    case MEC_MCR:		/* 0x00 */
	*data = mec_mcr;
	break;

    case MEC_MEMCFG:		/* 0x10 */
	*data = mec_memcfg;
	break;

    case MEC_IOCR:
	*data = mec_iocr;	/* 0x14 */
	break;

    case MEC_SSA1:		/* 0x20 */
	*data = mec_ssa[0] | (mec_wpr[0] << 23);
	break;
    case MEC_SEA1:		/* 0x24 */
	*data = mec_sea[0];
	break;
    case MEC_SSA2:		/* 0x28 */
	*data = mec_ssa[1] | (mec_wpr[1] << 23);
	break;
    case MEC_SEA2:		/* 0x2c */
	*data = mec_sea[1];
	break;

    case MEC_ISR:		/* 0x44 */
	*data = mec_isr;
	break;

    case MEC_IPR:		/* 0x48 */
	*data = mec_ipr;
	break;

    case MEC_IMR:		/* 0x4c */
	*data = mec_imr;
	break;

    case MEC_IFR:		/* 0x54 */
	*data = mec_ifr;
	break;

    case MEC_RTC_COUNTER:	/* 0x80 */
	*data = rtc_counter_read();
	break;
    case MEC_RTC_SCALER:	/* 0x84 */
	if (rtc_enabled)
	    *data = rtc_scaler - (now() - rtc_scaler_start);
	else
	    *data = rtc_scaler;
	break;

    case MEC_GPT_COUNTER:	/* 0x88 */
	*data = gpt_counter_read();
	break;

    case MEC_GPT_SCALER:	/* 0x8c */
	if (rtc_enabled)
	    *data = gpt_scaler - (now() - gpt_scaler_start);
	else
	    *data = gpt_scaler;
	break;


    case MEC_SFSR:		/* 0xA0 */
	*data = mec_sfsr;
	break;

    case MEC_FFAR:		/* 0xA4 */
	*data = mec_ffar;
	break;

    case SIM_LOAD:
	fname[find] = 0;
	if (find == 0)
	    strcpy(fname, "simload");
	find = bfd_load(fname);
 	if (find == -1) 
	    *data = 0;
	else
	    *data = 1;
	find = 0;
	break;

    case MEC_ERSR:		/* 0xB0 */
	*data = mec_ersr;
	break;

    case MEC_TCR:		/* 0xD0 */
	*data = mec_tcr;
	break;

    case MEC_UARTA:		/* 0xE0 */
    case MEC_UARTB:		/* 0xE4 */
	if (asi != 0xb) {
	    set_sfsr(MEC_ACC, addr, asi, 1);
	    return 1;
	}
	*data = read_uart(addr);
	break;

    case MEC_UART_CTRL:		/* 0xE8 */

	*data = read_uart(addr);
	break;

    case 0xF4:		/* simulator RAM size in bytes */
	*data = 4096*1024;
	break;

    case 0xF8:		/* simulator ROM size in bytes */
	*data = 1024*1024;
	break;

    default:
	set_sfsr(MEC_ACC, addr, asi, 1);
	return 1;
	break;
    }
    return MOK;
}

static int
mec_write(uint32_t addr, uint32_t data)
{
    if (sis_verbose > 1)
	printf("MEC write a: %08x, d: %08x\n",addr,data);
    switch (addr & 0x0ff) {

    case MEC_MCR:
	mec_mcr = data;
	decode_mcr();
        if (mec_mcr & 0x08000) mecparerror();
	break;

    case MEC_SFR:
	if (mec_mcr & 0x2) {
	    sys_reset();
	    mec_ersr = 0x4000;
    	    if (sis_verbose)
	    	printf(" Software reset issued\n");
	}
	break;

    case MEC_IOCR:
	mec_iocr = data;
        if (mec_iocr & 0xC0C0C0C0) mecparerror();
	break;

    case MEC_SSA1:		/* 0x20 */
        if (data & 0xFE000000) mecparerror();
	mec_ssa[0] = data & 0x7fffff;
	mec_wpr[0] = (data >> 23) & 0x03;
	mem_accprot = mec_wpr[0] || mec_wpr[1];
	if (sis_verbose && mec_wpr[0])
	    printf("Segment 1 memory protection enabled (0x02%06x - 0x02%06x)\n",
		   mec_ssa[0] << 2, mec_sea[0] << 2);
	break;
    case MEC_SEA1:		/* 0x24 */
        if (data & 0xFF800000) mecparerror();
	mec_sea[0] = data & 0x7fffff;
	break;
    case MEC_SSA2:		/* 0x28 */
        if (data & 0xFE000000) mecparerror();
	mec_ssa[1] = data & 0x7fffff;
	mec_wpr[1] = (data >> 23) & 0x03;
	mem_accprot = mec_wpr[0] || mec_wpr[1];
	if (sis_verbose && mec_wpr[1])
	    printf("Segment 2 memory protection enabled (0x02%06x - 0x02%06x)\n",
		   mec_ssa[1] << 2, mec_sea[1] << 2);
	break;
    case MEC_SEA2:		/* 0x2c */
        if (data & 0xFF800000) mecparerror();
	mec_sea[1] = data & 0x7fffff;
	break;

    case MEC_UARTA:
    case MEC_UARTB:
        if (data & 0xFFFFFF00) mecparerror();
    case MEC_UART_CTRL:
        if (data & 0xFF00FF00) mecparerror();
	write_uart(addr, data);
	break;

    case MEC_GPT_RELOAD:
	gpt_reload_set(data);
	break;

    case MEC_GPT_SCALER:
        if (data & 0xFFFF0000) mecparerror();
	gpt_scaler_set(data);
	break;

    case MEC_TIMER_CTRL:
        if (data & 0xFFFFF0F0) mecparerror();
	timer_ctrl(data);
	break;

    case MEC_RTC_RELOAD:
	rtc_reload_set(data);
	break;

    case MEC_RTC_SCALER:
        if (data & 0xFFFFFF00) mecparerror();
	rtc_scaler_set(data);
	break;

    case MEC_SFSR:		/* 0xA0 */
        if (data & 0xFFFF0880) mecparerror();
	mec_sfsr = 0x78;
	break;

    case MEC_ISR:
        if (data & 0xFFFFE000) mecparerror();
	mec_isr = data;
	break;

    case MEC_IMR:		/* 0x4c */

        if (data & 0xFFFF8001) mecparerror();
	mec_imr = data & 0x7ffe;
	chk_irq();
	break;

    case MEC_ICR:		/* 0x50 */

        if (data & 0xFFFF0001) mecparerror();
	mec_ipr &= ~data & 0x0fffe;
	chk_irq();
	break;

    case MEC_IFR:		/* 0x54 */

        if (mec_tcr & 0x080000) {
            if (data & 0xFFFF0001) mecparerror();
	    mec_ifr = data & 0xfffe;
	    chk_irq();
	}
	break;
    case SIM_LOAD:
	fname[find++] = (char) data;
	break;


    case MEC_MEMCFG:		/* 0x10 */
        if (data & 0xC0E08000) mecparerror();
	mec_memcfg = data;
	decode_memcfg();
	if (mec_memcfg & 0xc0e08000)
	    mecparerror();
	break;

    case MEC_WCR:		/* 0x18 */
	mec_wcr = data;
	decode_wcr();
	break;

    case MEC_ERSR:		/* 0xB0 */
	if (mec_tcr & 0x100000)
	  if (data & 0xFFFFEFC0) mecparerror();
	    mec_ersr = data & 0x103f;
	break;

    case MEC_TCR:		/* 0xD0 */
        if (data & 0xFFE1FFC0) mecparerror();
	mec_tcr = data & 0x1e003f;
	break;

    case MEC_WDOG:		/* 0x60 */
	wdog_scaler = (data >> 16) & 0x0ff;
	wdog_counter = data & 0x0ffff;
	wdog_rst_delay = data >> 24;
	wdog_rston = 0;
	if (wdog_status == stopped)
	    wdog_start();
	wdog_status = enabled;
	break;

    case MEC_TRAPD:		/* 0x64 */
	if (wdog_status == init) {
	    wdog_status = disabled;
	    if (sis_verbose)
		printf("Watchdog disabled\n");
	}
	break;

    case MEC_PWDR:
	if (mec_mcr & 1)
	    wait_for_irq();
	break;

    default:
	set_sfsr(MEC_ACC, addr, 0xb, 0);
	return 1;
	break;
    }
    return MOK;
}


/* MEC UARTS */

static int      ifd1 = -1, ifd2 = -1, ofd1 = -1, ofd2 = -1;

void
init_stdio(void)
{
    if (dumbio)
        return; /* do nothing */
#ifdef HAVE_TERMIOS_H
    if (!ifd1)
	tcsetattr(0, TCSANOW, &ioc1);
    if (!ifd2)
	tcsetattr(0, TCSANOW, &ioc2);
#endif
}

void
restore_stdio(void)
{
    if (dumbio)
        return; /* do nothing */
#ifdef HAVE_TERMIOS_H
    if (!ifd1)
	tcsetattr(0, TCSANOW, &iocold1);
    if (!ifd2)
	tcsetattr(0, TCSANOW, &iocold2);
#endif
}

#define DO_STDIO_READ( _fd_, _buf_, _len_ )          \
             ( dumbio                                \
               ? (0) /* no bytes read, no delay */   \
               : read( _fd_, _buf_, _len_ ) )


static void
port_init(void)
{

    if (uben) {
    f2in = stdin;
    f1in = NULL;
    f2out = stdout;
    f1out = NULL;
    } else {
    f1in = stdin;
    f2in = NULL;
    f1out = stdout;
    f2out = NULL;
    }
    if (uart_dev1[0] != 0) {
	if ((fd1 = open(uart_dev1, O_RDWR | O_NONBLOCK)) < 0) {
	    printf("Warning, couldn't open output device %s\n", uart_dev1);
	} else {
	    if (sis_verbose)
		printf("serial port A on %s\n", uart_dev1);
	    f1in = f1out = fdopen(fd1, "r+");
	    setbuf(f1out, NULL);
	    f1open = 1;
	}
    }
    if (f1in) ifd1 = fileno(f1in);
    if (ifd1 == 0) {
	if (sis_verbose)
	    printf("serial port A on stdin/stdout\n");
        if (!dumbio) {
#ifdef HAVE_TERMIOS_H
            tcgetattr(ifd1, &ioc1);
            iocold1 = ioc1;
            ioc1.c_lflag &= ~(ICANON | ECHO);
            ioc1.c_cc[VMIN] = 0;
            ioc1.c_cc[VTIME] = 0;
#endif
        }
	f1open = 1;
    }

    if (f1out) {
	ofd1 = fileno(f1out);
    	if (!dumbio && ofd1 == 1) setbuf(f1out, NULL);
    }

    if (uart_dev2[0] != 0) {
	if ((fd2 = open(uart_dev2, O_RDWR | O_NONBLOCK)) < 0) {
	    printf("Warning, couldn't open output device %s\n", uart_dev2);
	} else {
	    if (sis_verbose)
		printf("serial port B on %s\n", uart_dev2);
	    f2in = f2out = fdopen(fd2, "r+");
	    setbuf(f2out, NULL);
	    f2open = 1;
	}
    }
    if (f2in)  ifd2 = fileno(f2in);
    if (ifd2 == 0) {
	if (sis_verbose)
	    printf("serial port B on stdin/stdout\n");
        if (!dumbio) {
#ifdef HAVE_TERMIOS_H
            tcgetattr(ifd2, &ioc2);
            iocold2 = ioc2;
            ioc2.c_lflag &= ~(ICANON | ECHO);
            ioc2.c_cc[VMIN] = 0;
            ioc2.c_cc[VTIME] = 0;
#endif
        }
	f2open = 1;
    }

    if (f2out) {
	ofd2 = fileno(f2out);
        if (!dumbio && ofd2 == 1) setbuf(f2out, NULL);
    }

    wnuma = wnumb = 0;

}

static uint32_t
read_uart(uint32_t addr)
{

    unsigned        tmp;

    tmp = 0;
    switch (addr & 0xff) {

    case 0xE0:			/* UART 1 */
#ifndef _WIN32
#ifdef FAST_UART

	if (aind < anum) {
	    if ((aind + 1) < anum)
		mec_irq(4);
	    return (0x700 | (uint32_t) aq[aind++]);
	} else {
	    if (f1open) {
	        anum = DO_STDIO_READ(ifd1, aq, UARTBUF);
	    }
	    if (anum > 0) {
		aind = 0;
		if ((aind + 1) < anum)
		    mec_irq(4);
		return (0x700 | (uint32_t) aq[aind++]);
	    } else {
		return (0x600 | (uint32_t) aq[aind]);
	    }

	}
#else
	tmp = uarta_data;
	uarta_data &= ~UART_DR;
	uart_stat_reg &= ~UARTA_DR;
	return tmp;
#endif
#else
	return 0;
#endif
	break;

    case 0xE4:			/* UART 2 */
#ifndef _WIN32
#ifdef FAST_UART
	if (bind < bnum) {
	    if ((bind + 1) < bnum)
		mec_irq(5);
	    return (0x700 | (uint32_t) bq[bind++]);
	} else {
	    if (f2open) {
		bnum = DO_STDIO_READ(ifd2, bq, UARTBUF);
	    }
	    if (bnum > 0) {
		bind = 0;
		if ((bind + 1) < bnum)
		    mec_irq(5);
		return (0x700 | (uint32_t) bq[bind++]);
	    } else {
		return (0x600 | (uint32_t) bq[bind]);
	    }

	}
#else
	tmp = uartb_data;
	uartb_data &= ~UART_DR;
	uart_stat_reg &= ~UARTB_DR;
	return tmp;
#endif
#else
	return 0;
#endif
	break;

    case 0xE8:			/* UART status register	 */
#ifndef _WIN32
#ifdef FAST_UART

	Ucontrol = 0;
	if (aind < anum) {
	    Ucontrol |= 0x00000001;
	} else {
	    if (f1open) {
	        anum = DO_STDIO_READ(ifd1, aq, UARTBUF);
            }
	    if (anum > 0) {
		Ucontrol |= 0x00000001;
		aind = 0;
		mec_irq(4);
	    }
	}
	if (bind < bnum) {
	    Ucontrol |= 0x00010000;
	} else {
	    if (f2open) {
		bnum = DO_STDIO_READ(ifd2, bq, UARTBUF);
	    }
	    if (bnum > 0) {
		Ucontrol |= 0x00010000;
		bind = 0;
		mec_irq(5);
	    }
	}

	Ucontrol |= 0x00060006;
	return Ucontrol;
#else
	return uart_stat_reg;
#endif
#else
	return 0x00060006;
#endif
	break;
    default:
	if (sis_verbose)
	    printf("Read from unimplemented MEC register (%x)\n", addr);

    }
    return 0;
}

static void
write_uart(uint32_t addr, uint32_t data)
{
    unsigned char   c;

    c = (unsigned char) data;
    switch (addr & 0xff) {

    case 0xE0:			/* UART A */
#ifdef FAST_UART
	if (f1open) {
	    if (wnuma < UARTBUF)
	        wbufa[wnuma++] = c;
	    else {
	        while (wnuma)
		    wnuma -= fwrite(wbufa, 1, wnuma, f1out);
	        wbufa[wnuma++] = c;
	    }
	}
	mec_irq(4);
#else
	if (uart_stat_reg & UARTA_SRE) {
	    uarta_sreg = c;
	    uart_stat_reg &= ~UARTA_SRE;
	    event(uarta_tx, 0, UART_TX_TIME);
	} else {
	    uarta_hreg = c;
	    uart_stat_reg &= ~UARTA_HRE;
	}
#endif
	break;

    case 0xE4:			/* UART B */
#ifdef FAST_UART
	if (f2open) {
	    if (wnumb < UARTBUF)
		wbufb[wnumb++] = c;
	    else {
		while (wnumb)
		    wnumb -= fwrite(wbufb, 1, wnumb, f2out);
		wbufb[wnumb++] = c;
	    }
	}
	mec_irq(5);
#else
	if (uart_stat_reg & UARTB_SRE) {
	    uartb_sreg = c;
	    uart_stat_reg &= ~UARTB_SRE;
	    event(uartb_tx, 0, UART_TX_TIME);
	} else {
	    uartb_hreg = c;
	    uart_stat_reg &= ~UARTB_HRE;
	}
#endif
	break;
    case 0xE8:			/* UART status register */
#ifndef FAST_UART
	if (data & UARTA_CLR) {
	    uart_stat_reg &= 0xFFFF0000;
	    uart_stat_reg |= UARTA_SRE | UARTA_HRE;
	}
	if (data & UARTB_CLR) {
	    uart_stat_reg &= 0x0000FFFF;
	    uart_stat_reg |= UARTB_SRE | UARTB_HRE;
	}
#endif
	break;
    default:
	if (sis_verbose)
	    printf("Write to unimplemented MEC register (%x)\n", addr);

    }
}

static void
flush_uart(void)
{
    while (wnuma && f1open)
	wnuma -= fwrite(wbufa, 1, wnuma, f1out);
    while (wnumb && f2open)
	wnumb -= fwrite(wbufb, 1, wnumb, f2out);
}

ATTRIBUTE_UNUSED
static void
uarta_tx(void)
{

    while (f1open && fwrite(&uarta_sreg, 1, 1, f1out) != 1);
    if (uart_stat_reg & UARTA_HRE) {
	uart_stat_reg |= UARTA_SRE;
    } else {
	uarta_sreg = uarta_hreg;
	uart_stat_reg |= UARTA_HRE;
	event(uarta_tx, 0, UART_TX_TIME);
    }
    mec_irq(4);
}

ATTRIBUTE_UNUSED
static void
uartb_tx(void)
{
    while (f2open && fwrite(&uartb_sreg, 1, 1, f2out) != 1);
    if (uart_stat_reg & UARTB_HRE) {
	uart_stat_reg |= UARTB_SRE;
    } else {
	uartb_sreg = uartb_hreg;
	uart_stat_reg |= UARTB_HRE;
	event(uartb_tx, 0, UART_TX_TIME);
    }
    mec_irq(5);
}

ATTRIBUTE_UNUSED
static void
uart_rx(void *arg)
{
    int32_t           rsize;
    char            rxd;


    rsize = 0;
    if (f1open)
        rsize = DO_STDIO_READ(ifd1, &rxd, 1);
    if (rsize > 0) {
	uarta_data = UART_DR | rxd;
	if (uart_stat_reg & UARTA_HRE)
	    uarta_data |= UART_THE;
	if (uart_stat_reg & UARTA_SRE)
	    uarta_data |= UART_TSE;
	if (uart_stat_reg & UARTA_DR) {
	    uart_stat_reg |= UARTA_OR;
	    mec_irq(7);		/* UART error interrupt */
	}
	uart_stat_reg |= UARTA_DR;
	mec_irq(4);
    }
    rsize = 0;
    if (f2open)
        rsize = DO_STDIO_READ(ifd2, &rxd, 1);
    if (rsize) {
	uartb_data = UART_DR | rxd;
	if (uart_stat_reg & UARTB_HRE)
	    uartb_data |= UART_THE;
	if (uart_stat_reg & UARTB_SRE)
	    uartb_data |= UART_TSE;
	if (uart_stat_reg & UARTB_DR) {
	    uart_stat_reg |= UARTB_OR;
	    mec_irq(7);		/* UART error interrupt */
	}
	uart_stat_reg |= UARTB_DR;
	mec_irq(5);
    }
    event(uart_rx, 0, UART_RX_TIME);
}

static void
uart_intr(void *arg)
{
    read_uart(0xE8);		/* Check for UART interrupts every 1000 clk */
    flush_uart();		/* Flush UART ports      */
    event(uart_intr, 0, UART_FLUSH_TIME);
}


static void
uart_irq_start(void)
{
#ifdef FAST_UART
    event(uart_intr, 0, UART_FLUSH_TIME);
#else
#ifndef _WIN32
    event(uart_rx, 0, UART_RX_TIME);
#endif
#endif
}

/* Watch-dog */

static void
wdog_intr(void *arg)
{
    if (wdog_status == disabled) {
	wdog_status = stopped;
    } else {

	if (wdog_counter) {
	    wdog_counter--;
	    event(wdog_intr, 0, wdog_scaler + 1);
	} else {
	    if (wdog_rston) {
		printf("Watchdog reset!\n");
		sys_reset();
		mec_ersr = 0xC000;
	    } else {
		mec_irq(15);
		wdog_rston = 1;
		wdog_counter = wdog_rst_delay;
		event(wdog_intr, 0, wdog_scaler + 1);
	    }
	}
    }
}

static void
wdog_start(void)
{
    event(wdog_intr, 0, wdog_scaler + 1);
    if (sis_verbose)
	printf("Watchdog started, scaler = %d, counter = %d\n",
	       wdog_scaler, wdog_counter);
}


/* MEC timers */


static void
rtc_intr(void *arg)
{
    if (rtc_counter == 0) {

	mec_irq(13);
	if (rtc_cr)
	    rtc_counter = rtc_reload;
	else
	    rtc_se = 0;
    } else
	rtc_counter -= 1;
    if (rtc_se) {
	event(rtc_intr, 0, rtc_scaler + 1);
	rtc_scaler_start = now();
	rtc_enabled = 1;
    } else {
	if (sis_verbose)
	    printf("RTC stopped\n\r");
	rtc_enabled = 0;
    }
}

static void
rtc_start(void)
{
    if (sis_verbose)
	printf("RTC started (period %d)\n\r", rtc_scaler + 1);
    event(rtc_intr, 0, rtc_scaler + 1);
    rtc_scaler_start = now();
    rtc_enabled = 1;
}

static uint32_t
rtc_counter_read(void)
{
    return rtc_counter;
}

static void
rtc_scaler_set(uint32_t val)
{
    rtc_scaler = val & 0x0ff;	/* eight-bit scaler only */
}

static void
rtc_reload_set(uint32_t val)
{
    rtc_reload = val;
}

static void
gpt_intr(void *arg)
{
    if (gpt_counter == 0) {
	mec_irq(12);
	if (gpt_cr)
	    gpt_counter = gpt_reload;
	else
	    gpt_se = 0;
    } else
	gpt_counter -= 1;
    if (gpt_se) {
	event(gpt_intr, 0, gpt_scaler + 1);
	gpt_scaler_start = now();
	gpt_enabled = 1;
    } else {
	if (sis_verbose)
	    printf("GPT stopped\n\r");
	gpt_enabled = 0;
    }
}

static void
gpt_start(void)
{
    if (sis_verbose)
	printf("GPT started (period %d)\n\r", gpt_scaler + 1);
    event(gpt_intr, 0, gpt_scaler + 1);
    gpt_scaler_start = now();
    gpt_enabled = 1;
}

static uint32_t
gpt_counter_read(void)
{
    return gpt_counter;
}

static void
gpt_scaler_set(uint32_t val)
{
    gpt_scaler = val & 0x0ffff;	/* 16-bit scaler */
}

static void
gpt_reload_set(uint32_t val)
{
    gpt_reload = val;
}

static void
timer_ctrl(uint32_t val)
{

    rtc_cr = ((val & TCR_TCRCR) != 0);
    if (val & TCR_TCRCL) {
	rtc_counter = rtc_reload;
    }
    if (val & TCR_TCRSL) {
    }
    rtc_se = ((val & TCR_TCRSE) != 0);
    if (rtc_se && (rtc_enabled == 0))
	rtc_start();

    gpt_cr = (val & TCR_GACR);
    if (val & TCR_GACL) {
	gpt_counter = gpt_reload;
    }
    if (val & TCR_GACL) {
    }
    gpt_se = (val & TCR_GASE) >> 2;
    if (gpt_se && (gpt_enabled == 0))
	gpt_start();
}

/* Store data in host byte order.  MEM points to the beginning of the
   emulated memory; WADDR contains the index the emulated memory,
   DATA points to words in host byte order to be stored.  SZ contains log(2)
   of the number of bytes to retrieve, and can be 0 (1 byte), 1 (one half-word),
   2 (one word), or 3 (two words); WS should return the number of
   wait-states.  */

static void
store_bytes (unsigned char *mem, uint32_t waddr, uint32_t *data, int32_t sz,
	     int32_t *ws)
{
    switch (sz) {
	case 0:
	    waddr ^= EBT;
	    mem[waddr] = *data & 0x0ff;
	    *ws = mem_ramw_ws + 3;
	    break;
	case 1:
#ifdef HOST_LITTLE_ENDIAN
	    waddr ^= 2;
#endif
	    memcpy (&mem[waddr], data, 2);
	    *ws = mem_ramw_ws + 3;
	    break;
	case 2:
	    memcpy (&mem[waddr], data, 4);
	    *ws = mem_ramw_ws;
	    break;
	case 3:
	    memcpy (&mem[waddr], data, 8);
	    *ws = 2 * mem_ramw_ws + STD_WS;
	    break;
    }
}


/* Memory emulation */

int
memory_iread (uint32_t addr, uint32_t *data, uint32_t *ws)
{
    uint32_t          asi;
    if ((addr >= mem_ramstart) && (addr < (mem_ramstart + mem_ramsz))) {
	memcpy (data, &ramb[addr & mem_rammask & ~3], 4);
	*ws = mem_ramr_ws;
	return 0;
    } else if (addr < mem_romsz) {
	memcpy (data, &romb[addr & ~3], 4);
	*ws = mem_romr_ws;
	return 0;
    }

    if (sis_verbose)
	printf ("Memory exception at %x (illegal address)\n", addr);
    if (sregs.psr & 0x080)
        asi = 9;
    else
        asi = 8;
    set_sfsr (UIMP_ACC, addr, asi, 1);
    *ws = MEM_EX_WS;
    return 1;
}

int
memory_read(int32_t asi, uint32_t addr, void *data, int32_t sz, int32_t *ws)
{
    int32_t           mexc;

#ifdef ERRINJ
    if (errmec) {
	if (sis_verbose)
	    printf("Inserted MEC error %d\n",errmec);
	set_sfsr(errmec, addr, asi, 1);
	if (errmec == 5) mecparerror();
	if (errmec == 6) iucomperr();
	errmec = 0;
	return 1;
    }
#endif

    if ((addr >= mem_ramstart) && (addr < (mem_ramstart + mem_ramsz))) {
	memcpy (data, &ramb[addr & mem_rammask & ~3], 4);
	*ws = mem_ramr_ws;
	return 0;
    } else if ((addr >= MEC_START) && (addr < MEC_END)) {
	mexc = mec_read(addr, asi, data);
	if (mexc) {
	    set_sfsr(MEC_ACC, addr, asi, 1);
	    *ws = MEM_EX_WS;
	} else {
	    *ws = 0;
	}
	return mexc;

#ifdef ERA

    } else if (era) {
    	if ((addr < 0x100000) || 
	    ((addr>= 0x80000000) && (addr < 0x80100000))) {
	    memcpy (data, &romb[addr & ROM_MASK & ~3], 4);
	    *ws = 4;
	    return 0;
	} else if ((addr >= 0x10000000) && 
		   (addr < (0x10000000 + (512 << (mec_iocr & 0x0f)))) &&
		   (mec_iocr & 0x10))  {
	    memcpy (data, &erareg, 4);
	    return 0;
	}
	
    } else  if (addr < mem_romsz) {
	memcpy (data, &romb[addr & ~3], 4);
	*ws = mem_romr_ws;
	return 0;
#else
    } else if (addr < mem_romsz) {
	memcpy (data, &romb[addr & ~3], 4);
	*ws = mem_romr_ws;
	return 0;
#endif

    }

    if (sis_verbose)
	printf ("Memory exception at %x (illegal address)\n", addr);
    set_sfsr(UIMP_ACC, addr, asi, 1);
    *ws = MEM_EX_WS;
    return 1;
}

int
memory_write(int32_t asi, uint32_t addr, uint32_t *data, int32_t sz, int32_t *ws)
{
    uint32_t          byte_addr;
    uint32_t          byte_mask;
    uint32_t          waddr;
    uint32_t         *ram;
    int32_t           mexc;
    int             i;
    int             wphit[2];

#ifdef ERRINJ
    if (errmec) {
	if (sis_verbose)
	    printf("Inserted MEC error %d\n",errmec);
	set_sfsr(errmec, addr, asi, 0);
	if (errmec == 5) mecparerror();
	if (errmec == 6) iucomperr();
	errmec = 0;
	return 1;
    }
#endif

    if ((addr >= mem_ramstart) && (addr < (mem_ramstart + mem_ramsz))) {
	if (mem_accprot) {

	    waddr = (addr & 0x7fffff) >> 2;
	    for (i = 0; i < 2; i++)
		wphit[i] =
		    (((asi == 0xa) && (mec_wpr[i] & 1)) ||
		     ((asi == 0xb) && (mec_wpr[i] & 2))) &&
		    ((waddr >= mec_ssa[i]) && ((waddr | (sz == 3)) < mec_sea[i]));

	    if (((mem_blockprot) && (wphit[0] || wphit[1])) ||
		((!mem_blockprot) &&
		 !((mec_wpr[0] && wphit[0]) || (mec_wpr[1] && wphit[1]))
		 )) {
		if (sis_verbose)
		    printf("Memory access protection error at 0x%08x\n", addr);
		set_sfsr(PROT_EXC, addr, asi, 0);
		*ws = MEM_EX_WS;
		return 1;
	    }
	}
	waddr = addr & mem_rammask;
	store_bytes (ramb, waddr, data, sz, ws);
	return 0;
    } else if ((addr >= MEC_START) && (addr < MEC_END)) {
	if ((sz != 2) || (asi != 0xb)) {
	    set_sfsr(MEC_ACC, addr, asi, 0);
	    *ws = MEM_EX_WS;
	    return 1;
	}
	mexc = mec_write(addr, *data);
	if (mexc) {
	    set_sfsr(MEC_ACC, addr, asi, 0);
	    *ws = MEM_EX_WS;
	} else {
	    *ws = 0;
	}
	return mexc;

#ifdef ERA

    } else if (era) {
    	if ((erareg & 2) && 
	((addr < 0x100000) || ((addr >= 0x80000000) && (addr < 0x80100000)))) {
	    addr &= ROM_MASK;
	    *ws = sz == 3 ? 8 : 4;
	    store_bytes (romb, addr, data, sz, ws);
            return 0;
	} else if ((addr >= 0x10000000) && 
		   (addr < (0x10000000 + (512 << (mec_iocr & 0x0f)))) &&
		   (mec_iocr & 0x10))  {
	    erareg = *data & 0x0e;
	    return 0;
	}

    } else if ((addr < mem_romsz) && (mec_memcfg & 0x10000) && (wrp) &&
               (((mec_memcfg & 0x20000) && (sz > 1)) || 
		(!(mec_memcfg & 0x20000) && (sz == 0)))) {

	*ws = mem_romw_ws + 1;
	if (sz == 3)
	    *ws += mem_romw_ws + STD_WS;
	store_bytes (romb, addr, data, sz, ws);
        return 0;

#else
    } else if ((addr < mem_romsz) && (mec_memcfg & 0x10000) && (wrp) &&
               (((mec_memcfg & 0x20000) && (sz > 1)) || 
		(!(mec_memcfg & 0x20000) && (sz == 0)))) {

	*ws = mem_romw_ws + 1;
	if (sz == 3)
            *ws += mem_romw_ws + STD_WS;
	store_bytes (romb, addr, data, sz, ws);
        return 0;

#endif

    }
	
    *ws = MEM_EX_WS;
    set_sfsr(UIMP_ACC, addr, asi, 0);
    return 1;
}

static void  *
get_mem_ptr(uint32_t addr, uint32_t size)
{
    if ((addr + size) < ROM_SZ) {
	return &romb[addr];
    } else if ((addr >= mem_ramstart) && ((addr + size) < mem_ramend)) {
	return &ramb[addr & mem_rammask];
    }

#ifdef ERA
      else if ((era) && ((addr <0x100000) || 
	((addr >= (unsigned) 0x80000000) && ((addr + size) < (unsigned) 0x80100000)))) {
	return &romb[addr & ROM_MASK];
    }
#endif

    return (void *) -1;
}

int
sis_memory_write(uint32_t addr, const void *data, uint32_t length)
{
    void           *mem;

    if ((mem = get_mem_ptr(addr, length)) == ((void *) -1))
	return 0;

    memcpy(mem, data, length);
    return length;
}

int
sis_memory_read(uint32_t addr, void *data, uint32_t length)
{
    char           *mem;

    if ((mem = get_mem_ptr(addr, length)) == ((void *) -1))
	return 0;

    memcpy(data, mem, length);
    return length;
}

extern struct pstate sregs;

void
boot_init (void)
{
    mec_write(MEC_WCR, 0);	/* zero waitstates */
    mec_write(MEC_TRAPD, 0);	/* turn off watch-dog */
    mec_write(MEC_RTC_SCALER, sregs.freq - 1); /* generate 1 MHz RTC tick */
    mec_write(MEC_MEMCFG, (3 << 18) | (4 << 10)); /* 1 MB ROM, 4 MB RAM */
    sregs.wim = 2;
    sregs.psr = 0x110010e0;
    sregs.r[30] = RAM_END;
    sregs.r[14] = sregs.r[30] - 96 * 4;
    mec_mcr |= 1;		/* power-down enabled */
}