/**************************************************************************
 *                                                                        *
 *               Copyright (C) 1994, Silicon Graphics, Inc.               *
 *                                                                        *
 *  These coded instructions, statements, and computer programs  contain  *
 *  unpublished  proprietary  information of Silicon Graphics, Inc., and  *
 *  are protected by Federal copyright  law.  They  may not be disclosed  *
 *  to  third  parties  or copied or duplicated in any form, in whole or  *
 *  in part, without the prior written consent of Silicon Graphics, Inc.  *
 *                                                                        *
 *************************************************************************/

/*
 * File:	disasm.c
 * Creator:	hsa@sgi.com
 * Create Date:	Fri Feb 11 13:20:04 PST 1994
 *
 * This file has some functions to disassemble an instruction.
 *
 * Compile this with -DDUMPMODE and it generates a stand-alone program
 * that will printout the opcode syntax for each op.
 *
 */

#include <stdio.h>
#include "rsp.h"
#include "opcode.h"
#include "disasm.h"

unsigned int regsUsed;

/*
 * search op table for a match:
 * 'first' field skips parts of the table to avoid duplicate codes.
 * 
 */
static rsp_disOp_t *
find_op(int opKey, char *first)
{
    rsp_disOp_t	*tp = &(rsp_disOpTable[0]);

    /* skip first part (SPECIAL/REGIMM/COP re-use codes) */
    while (strcmp(first, tp->opString) != 0)
	tp++;

    /* find the right one: */
    while( (tp->opKey != rsp_FINALOP) && (tp->opKey != rsp_FIN) ) {
	if (tp->opKey == opKey) {
	    return tp;
	}
	tp++;
    }

    return(NULL);
}

/*
 * This little parser fills in the "template" for each
 * op. It doesn't have to know anything about the instructions,
 * the template encodes what fields to print out and how.
 * Result returned in 'buf'
 */
static void
fill_template(char *temp, char *buf, 
	      int rs, int rt, int rd, int sa, int immed, int target, int cur_pc )
{
    char 	c, tmpbuf[32], *bp = buf, *tp;
    int addr;

    bzero(bp, 32);	/* buf must be at least this big */
    regsUsed = 0;

    while ((c = *temp++) != '\0') {
	if (c == '%') {
	    c = *temp++;
	    switch (c) {
	      case 's': /* %s - replace with 5-bit source (or base) register */
#ifdef DUMPMODE
		sprintf(tmpbuf, "rs", rs);
#else
		sprintf(tmpbuf, "%d", rs);
		regsUsed |= (1 << rs);
#endif
		break;
		
	      case 't': /* %t - replace with 5-bit target register */
#ifdef DUMPMODE
		sprintf(tmpbuf, "rt", rt);
#else
		sprintf(tmpbuf, "%d", rt);
		regsUsed |= (1 << rt);
#endif
		break;
		
	      case 'i': /* %i - replace with 16-bit immediate (offset) value */
#ifdef DUMPMODE
		sprintf(tmpbuf, "immed", immed);
#else
		sprintf(tmpbuf, "0x%04x", immed);
#endif
		break;
		
	      case 'I': /* %I - replace with 16-bit immediate (offset) value */
#ifdef DUMPMODE
		sprintf(tmpbuf, "immed", immed);	/* decimal number */
#else
		sprintf(tmpbuf, "%d", immed);	/* decimal number */
#endif
		break;
		
	      case 'O': /* %O - replace with 16-bit offset value */
#ifdef DUMPMODE
		sprintf(tmpbuf, "offset", immed);	/* decimal number */
#else
		sprintf(tmpbuf, "%d", immed);	/* decimal number */
#endif
		break;

	      case 'o': /* %o - replace with 16-bit offset value + cur address */
#ifdef DUMPMODE
		sprintf(tmpbuf, "offset", immed);	/* hex address */
#else
		addr = (4*immed) + cur_pc+4;
		sprintf(tmpbuf, "0x%03x", addr & 0xffc);/* hex address */
#endif
		break;
		
	      case 'a': /* %a - replace with 26-bit target address */
#ifdef DUMPMODE
		sprintf(tmpbuf, "targ", target);
#else
		sprintf(tmpbuf, "0x%08x", 0x04001000 + ((target&0x3ff)<<2));
#endif
		break;
		
	      case 'd': /* %d - replace with 5-bit destination register */
#ifdef DUMPMODE
		sprintf(tmpbuf, "rd", rd);
#else
		sprintf(tmpbuf, "%d", rd);
		regsUsed |= (1 << rd);
#endif
		break;
		
	      case 'h': /* %h - replace with 5-bit shift amount */
#ifdef DUMPMODE
		sprintf(tmpbuf, "sa", sa);
#else
		sprintf(tmpbuf, "%d", sa);
#endif
		break;
		
	      case 'e': /* %e - replace with 3-bit element */
#ifdef DUMPMODE
		sprintf(tmpbuf, "e", sa);
#else
		sprintf(tmpbuf, "%d", sa);	/* re-use sa field */
#endif
		break;
		
	      case 'l': /* %l - replace with 3-bit (load/store) element */
#ifdef DUMPMODE
		sprintf(tmpbuf, "e", sa);
#else
		sprintf(tmpbuf, "%d", sa);	/* re-use sa field */
#endif
		break;
		
	      case 'f': /* %f - replace with 6-bit function code */
		/* not used... */
		break;
	    }
	    tp = &(tmpbuf[0]);
	    while (*tp != '\0')
		*bp++ = *tp++;
	} else {
	    *bp++ = c;
	}
    }
}


/*
 * dis-assemble an instruction and return a readable string
 * in the buffer 'buf'
 */
void
rsp_DisasmInst(u32 inst, char *buf, int pc)
{
    rsp_disOp_t	*opDisasm;
    int		opKey, rs, rt, rd, sa, target;
    short int	immed;
    char	tmpbuf[32];

    opKey = ExtractOpcode(inst);
    switch (opKey) {
      case rsp_SPECIAL:
	opKey = ExtractBits(inst, 5, 0);
	opDisasm = find_op(opKey, "add");
	if (opDisasm == (rsp_disOp_t *) NULL) {
	    sprintf(buf,"%s","BAD OP (SPECIAL)");
	    return;
	}

	/* SPECIAL instructions are all R-Type */
	rs = ExtractBits(inst, 25, 21);
	rt = ExtractBits(inst, 20, 16);
	rd = ExtractBits(inst, 15, 11);
	sa = ExtractBits(inst, 10, 6);
	fill_template(opDisasm->cmdFormat, buf, rs, rt, rd, sa, 0, 0, pc);
	if (inst == 0x00000000) {
	    sprintf(buf,"nop         ");	/* special case */
	}
	break;

      case rsp_REGIMM:
	opKey = ExtractBits(inst, 20, 16);
	opDisasm = find_op(opKey, "bltz");
	if (opDisasm == (rsp_disOp_t *) NULL) {
	    sprintf(buf,"%s","BAD OP (REGIMM)");
	    return;
	}

	/* REGIMM instructions are all I-Type */
	rs = ExtractBits(inst, 25, 21);
	rt = ExtractBits(inst, 20, 16);
	immed = ExtractBits(inst, 15, 0);
	fill_template(opDisasm->cmdFormat, buf, rs, rt, 0, 0, immed, 0, pc);
	break;

      case rsp_COP0:
	opKey = ExtractBits(inst, 25, 21);
	switch (opKey) {
	  case rsp_MFC0:
	  case rsp_MTC0:
	    opDisasm = find_op(opKey, "mfc0");
	    rt = ExtractBits(inst, 20, 16);
	    rd = ExtractBits(inst, 15, 11);
	    fill_template(opDisasm->cmdFormat, buf, 0, rt, rd, 0, 0, 0, pc);
	    break;

	  case rsp_BC0:
	    opKey = ExtractBits(inst, 20, 16);
	    if (opKey)
		opDisasm = find_op(rsp_BC0, "bc0t");
	    else
		opDisasm = find_op(rsp_BC0, "bc0f");
	    immed = ExtractBits(inst, 15, 0);
	    fill_template(opDisasm->cmdFormat, buf, 0, 0, 0, 0, immed, 0, pc);
	    break;
	  default:
	    sprintf(buf,"%s","BAD OP (COP0)");
	    break;
	}
	break;

      case rsp_COP2:
	opKey = ExtractBits(inst, 25, 21);
	if (opKey & 0x10) {	/* bit 25 is set */
	    opKey = ExtractBits(inst, 5, 0);
	    opDisasm = find_op(opKey, "vmulf");
	    if (opDisasm == (rsp_disOp_t *) NULL) {
		sprintf(buf,"%s","BAD OP (COP2)");
		return;
	    }
	    rs = ExtractBits(inst, 15, 11);
	    rt = ExtractBits(inst, 20, 16);
	    rd = ExtractBits(inst, 10, 6);
	    sa = ExtractBits(inst, 24, 21);	/* element */

	    if ((opKey & 0x38) == 0x38)	{ /* a pack instruction... */
		switch (sa) {
		  case 0x01:
		    sa = 0;
		    break;
		  case 0x02:
		    sa = 1;
		    break;
		  case 0x04:
		    sa = 2;
		    break;
		  case 0x08:
		    sa = 3;
		    break;
		  default:
		    sprintf(buf,"%s","BAD OP (VMUL)");
		    return;
		}
#ifdef DIV_DIFF
	    } else
	       if ((opKey & 0x38) == 0x30)	{ /* an rcp instruction... */
		rs &= 0x07;
		sa &= 0x07;
		tmpbuf[0] = '\0';
#endif
	    } else {
	        if ((opKey & 0x38) == 0x30)	/* an rcp instruction... */
	   	   rs &= 0x07;

	        if((opKey == rsp_VADDB) ||
	           (opKey == rsp_VSUBB) ||
	           (opKey == rsp_VACCB) ||
	           (opKey == rsp_VSUCB)   ) {

		   sa &= 7;
		   sa += 8;
		}
	        if (opKey == rsp_VSAW) { 	/* Actually VSAR */
		    sa &= 3;
		    if( sa == 3 ) {
			sprintf(buf,"%s","BAD OP (VSAR [3])");
			return;
		    };
		    sa += 8;
		};

		if (sa >= 8) {	/* 1 of 8 elements of whole */
		    sa &= 0x07;
		    sprintf(tmpbuf,"[%d]",sa);
		} else if (sa >= 4) { /* 1 of 4 elements of half */
		    sa &= 0x03;
		    sprintf(tmpbuf,"[%dh]",sa);
		} else if (sa >= 2) { /* 1 of 2 elements of quarter */
		    sa &= 0x01;
		    sprintf(tmpbuf,"[%dq]",sa);
		} else {
		    /* vector operand, no element */
		    tmpbuf[0] = '\0';
		}
	    }
	    fill_template(opDisasm->cmdFormat, buf, rs, rt, rd, sa, 0, 0, pc);

	    if ((opKey & 0x38) != 0x38)	/* not a pack instruction... */
		strcat(buf, tmpbuf);

	} else {		/* su cop2 instruction */
	    opDisasm = find_op(opKey, "mfc2");
	    if (opDisasm == (rsp_disOp_t *) NULL) {
		sprintf(buf,"%s","BAD OP (SU COP2)");
		return;
	    }
	    rt = ExtractBits(inst, 20, 16);
	    rd = ExtractBits(inst, 15, 11);
	    sa = ExtractBits(inst, 10, 7);
	    switch (opKey) {
	      case rsp_MFC2:
	      case rsp_MTC2:
		fill_template(opDisasm->cmdFormat, buf, 0, rt, rd, sa, 0, 0, pc);
		break;

	      case rsp_CFC2:
	      case rsp_CTC2:
		fill_template(opDisasm->cmdFormat, buf, 0, rt, rd, sa, 0, 0, pc);
		if( (rd&0x3) == 0 )
		    strcat( buf, "VCO" );
		else if( (rd&0x3) == 1 )
		    strcat( buf, "VCC" );
		else if( (rd&0x3) == 2 )
		    strcat( buf, "VCE" );
		else
		    if( opKey == rsp_CFC2 )
			sprintf(buf,"BAD OP (CFC2 %d)", rd);
		    else
			{
			    char tmpbuf[80];

			    sprintf( tmpbuf, "NOP(%d)", rd );
			    strcat( buf, tmpbuf );
		    };
		break;
	      default:
		sprintf(buf,"%s","BAD OP (COP2)");
		break;
	    }
	}
	break;

      case rsp_LWC2:
	opKey = ExtractBits(inst, 15, 11);
	opDisasm = find_op(opKey, "lbv");
	if (opDisasm == (rsp_disOp_t *) NULL) {
	    sprintf(buf,"%s","BAD OP (SU LOAD COP2)");
	    return;
	}
	rs = ExtractBits(inst, 25, 21);
	rt = ExtractBits(inst, 20, 16);
	sa = ExtractBits(inst, 10, 7);

	immed = ExtractBits(inst, 6, 0);

#define SignExtend(x,len)     ((((int)(x))<<(32-(len)))>>(32-(len)))

	immed = SignExtend( immed, 7 );

	switch (opDisasm->opString[1]) {
	  case 'b':
	    break;

	  case 's':
	    immed <<= 1;
	    break;

	  case 'l':
	    immed <<= 2;
	    break;

	  case 'd':
	  case 'p':
	  case 'u':
	  case 'a':
	    immed <<= 3;
	    break;

	  case 'q':
	  case 'r':
	  case 'h':
	  case 'f':
	  case 't':
	  case 'w':
	    immed <<= 4;
	    break;

	}
	fill_template(opDisasm->cmdFormat, buf, rs, rt, 0, sa, immed, 0, pc);
	break;

      case rsp_SWC2:
	opKey = ExtractBits(inst, 15, 11);
	opDisasm = find_op(opKey, "sbv");
	if (opDisasm == (rsp_disOp_t *) NULL) {
	    sprintf(buf,"%s","BAD OP (SU STORE COP2)");
	    return;
	}
	rs = ExtractBits(inst, 25, 21);
	rt = ExtractBits(inst, 20, 16);
	sa = ExtractBits(inst, 10, 7);
	immed = ExtractBits(inst, 6, 0);
	switch (opDisasm->opString[1]) {
	  case 'b':
	    break;

	  case 's':
	    immed <<= 1;
	    break;

	  case 'l':
	    immed <<= 2;
	    break;

	  case 'd':
	  case 'p':
	  case 'u':
	  case 'a':
	    immed <<= 3;
	    break;

	  case 'q':
	  case 'h':
	  case 'f':
	  case 't':
	    immed <<= 4;
	    break;

	}
	fill_template(opDisasm->cmdFormat, buf, rs, rt, 0, sa, immed, 0, pc);
	break;

      case rsp_J: case rsp_JAL:
      case rsp_BEQ: case rsp_BNE: case rsp_BLEZ: case rsp_BGTZ:

      case rsp_ADDI: case rsp_ADDIU:
      case rsp_SLTI: case rsp_SLTIU:
      case rsp_ANDI: case rsp_ORI:
      case rsp_XORI: case rsp_LUI:

      case rsp_LB: case rsp_LBU:
      case rsp_LH: case rsp_LHU:
      case rsp_LW:
      case rsp_SB: case rsp_SH: case rsp_SW:

	opDisasm = find_op(opKey, "special");
	if (opDisasm == (rsp_disOp_t *) NULL) {
	    sprintf(buf,"%s","BAD OP (REGULAR)");
	    return;
	}

	rs = ExtractBits(inst, 25, 21);
	rt = ExtractBits(inst, 20, 16);
	rd = ExtractBits(inst, 15, 11);
	sa = ExtractBits(inst, 10, 6);
	immed = ExtractBits(inst, 15, 0);
	target = ExtractBits(inst, 25, 0);

	fill_template(opDisasm->cmdFormat, buf, rs, rt, rd, sa, immed, target, pc);
	break;
      default:
	sprintf(buf,"BAD OP (REGULAR opKey=0x%02x)", opKey);
	break;
    }
}


#ifdef DUMPMODE
/*
 * Dump out all the opcodes and their syntax.
 *
 */
int
main(int argc, char *argv[])
{
    rsp_disOp_t	*opDisasm = &(rsp_disOpTable[0]);
    char	buffer[80];
    boolean	firstV = TRUE;

    while ((argc > 1) && (argv[1][0] == '-')) {
	switch(argv[1][1]) {
	}
	argc--;
	argv++;
    }

    fprintf(stdout,"\n\t\t\tRSP Instruction Set:\n");
    fprintf(stdout,"\t\t\t%s %s\n\n",RSP_VERSION_DATE, RSP_VERSION_TIME);

    while (opDisasm->opKey != rsp_FINALOP) {
	fill_template(opDisasm->cmdFormat, buffer, 0, 0, 0, 0, 0, 0, 0);

	if (buffer[0] == 'v' && firstV) {
	    fprintf(stdout,"\n\tRSP Vector Unit Operations:\n");
	    fprintf(stdout,"\tMost of these can have an element field for\n");
	    fprintf(stdout,"\tvrt also, which looks like $vrt[e]\n\n");
	    firstV = FALSE;
	}

	if (buffer[0] != '(')
	    fprintf(stdout,"  %s\t%s\n",buffer,opDisasm->helpString);

	opDisasm++;
    }

    fprintf(stdout,"\n");
}

#endif