--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/index.c	Fri Oct 03 02:44:20 2008 +0000
@@ -0,0 +1,315 @@
+/*
+ * index.c
+ *
+ * code for parsing indexed addressing modes
+ */
+
+#include <ctype.h>
+//#include <errno.h>
+//#include <stdio.h>
+//#include <stdlib.h>
+#include <string.h>
+#define __index_c_seen__
+//#include "instab.h"
+#include "lwasm.h"
+#include "instab.h"
+
+
+int parse_index_expr(asmstate_t *as, sourceline_t *cl, char **optr, int *postbyte, int *opmode, int *v1)
+{
+	static const char *regs = "X  Y  U  S  W  PCRPC ";
+	static const struct { char *opstr; int pb; } simpleindex[] =
+	{
+		{",x", 0x84},		{",y", 0xa4},		{",u", 0xc4},		{",s", 0xe4},
+		{",x+", 0x80},		{",y+", 0xa0},		{",u+", 0xc0},		{",s+", 0xe0},
+		{",x++", 0x81},		{",y++", 0xa1},		{",u++", 0xc1},		{",s++", 0xe1},
+		{",-x", 0x82},		{",-y", 0xa2},		{",-u", 0xc2},		{",-s", 0xe2},
+		{",--x", 0x83},		{",--y", 0xa3},		{",--u", 0xc3},		{",--s", 0xe3},
+		{"a,x", 0x86},		{"a,y", 0xa6},		{"a,u", 0xc6},		{"a,s", 0xe6},
+		{"b,x", 0x85},		{"b,y", 0xa5},		{"b,u", 0xc5},		{"b,s", 0xe5},
+		{"e,x", 0x87},		{"e,y", 0xa7},		{"e,u", 0xc7},		{"e,s", 0xe7},
+		{"f,x",	0x8a},		{"f,y",	0xaa},		{"f,u", 0xca},		{"f,s", 0xea},
+		{"d,x", 0x8b},		{"d,y", 0xab},		{"d,u", 0xcb},		{"d,s", 0xed},
+		{"w,x", 0x8e},		{"w,y", 0xae},		{"w,u", 0xce},		{"w,s", 0xee},
+		{",w", 0x8f},							{",w++", 0xcf},		{",--w", 0xef},
+		
+		{"[,x]", 0x94},		{"[,y]", 0xb4},		{"[,u", 0xd4},		{"[,s]", 0xf4},
+		{"[,x++]", 0x91},	{"[,y++]", 0xb1},	{"[,u++]", 0xd1},	{"[,s++]", 0xf1},
+		{"[,--x]", 0x93},	{"[,--y]", 0xb3},	{"[,--u]", 0xd3},	{"[,--s]", 0xf3},
+		{"[a,x]", 0x96},	{"[a,y]", 0xb6},	{"[a,u]", 0xd6},	{"[a,s]", 0xf6},
+		{"[b,x]", 0x95},	{"[b,y]", 0xb5},	{"[b,u]", 0xd5},	{"[b,s]", 0xf5},
+		{"[e,x]", 0x97},	{"[e,y]", 0xb7},	{"[e,u]", 0xd7},	{"[e,s]", 0xf7},
+		{"[f,x]", 0x9a},	{"[f,y]", 0xba},	{"[f,u]", 0xda},	{"[f,s]", 0xfa},
+		{"[d,x]", 0x9b},	{"[d,y]", 0xbb},	{"[d,u]", 0xdb},	{"[d,s]", 0xfd},
+		{"[w,x]", 0x9e},	{"[w,y]", 0xbe},	{"[w,u]", 0xde},	{"[w,s]", 0xfe},
+		{"[,w]", 0x90},							{"[,w++]", 0xd0},	{"[,--w]", 0xf0},
+		
+		{ "", -1 }
+	};
+	char stbuf[25];
+	int i;
+	int f8 = 0, f16 = 0;
+	int rn;
+	int indir = 0;
+	int rval;
+	int f0 = 0;
+ 
+	for (i = 0; i < 24; i++)
+	{
+		if (*((*optr) + i) && !isspace(*((*optr) + i)))
+			stbuf[i] = *((*optr) + i);
+		else
+			break;
+	}
+	stbuf[i] = '\0';
+	if (!*((*optr) + i) || isspace(*((*optr) + i)))
+	{
+		int j;
+		// do simple lookup
+		for (j = 0; simpleindex[j].opstr[0]; j++)
+		{
+			if (!strcasecmp(stbuf, simpleindex[j].opstr))
+				break;
+		}
+		if (simpleindex[j].opstr[0])
+		{
+			*postbyte = simpleindex[j].pb;
+			*opmode = OPER_INDEX;
+			(*optr) += i;
+			return 0;
+		}
+	}
+	
+	// now we have the hard ones to work out here
+	
+	if (**optr == '[')
+	{
+		indir = 1;
+		(*optr)++;
+	}
+	
+	rn = 0;
+	for (i = 0; (*optr)[i] && !isspace((*optr)[i]); i++)
+	{
+		if ((*optr)[i] == ',')
+		{
+			rn = 1;
+			break;
+		}
+	}
+		
+	if (!rn && indir)
+	{
+		// extended indir
+		*postbyte = 0x9f;
+		*opmode = OPER_EXTIND;
+		rval = eval_expr(as, cl, optr, v1);
+		if (**optr != ']')
+		{
+			errorp1(ERR_BADOPER);
+		}
+		(*optr)++;
+		return 0;
+	}
+
+	if (cl -> p1f16)
+		f16 = 1;	
+	if (**optr == '<')
+	{
+		f8 = 1;
+		(*optr)++;
+	}
+	else if (**optr == '>')
+	{
+		f16 = 1;
+		(*optr)++;
+	}
+
+	if (**optr == '0' && *(*optr+1) == ',')
+	{
+		f0 = 1;
+	}
+	
+	// now we have to evaluate the expression
+	rval = eval_expr(as, cl, optr, v1);
+
+	if (cl -> undef && as -> passnum == 1)
+	{
+		cl -> p1f16 = 1;
+		f16 = 1;
+	}
+
+	// now look for a comma; if not present, explode
+	if (rval == -1 || *(*optr)++ != ',')
+	{
+		// syntax error; force 0 bit
+		*postbyte = -1;
+		*opmode = OPER_INDEX;
+		return -2;
+	}
+	
+	// now get the register
+	rn = lookupreg3(regs, optr);
+	if (rn < 0)
+		goto reterr;
+
+//	debug("Reg: %d\n", rn);
+
+	if (indir && **optr != ']')
+		goto reterr;
+	else
+		(*optr)++;
+	
+	// nnnn,W is only 16 bit
+	if (rn == 4)
+	{
+		if (f8)
+			goto reterr;
+		if (!f16 && !f0 && !(as -> pragmas & PRAGMA_NOINDEX0TONONE) && *v1 == 0)
+		{
+			*opmode = OPER_INDEX;
+			if (indir)
+				*postbyte = 0x90;
+			else
+				*postbyte = 0x8f;
+			return 0;
+		}
+		*opmode = OPER_INDEX16;
+		if (indir)
+			*postbyte = 0xb0;
+		else
+			*postbyte = 0xcf;
+		return 0;
+	}
+	
+	if (indir) indir = 0x10;
+	
+	// forward ref; we can't figure anything
+	if (cl -> undef)
+	{
+		f16 = 1;
+	}
+
+	// PCR? redo v1, v2 relative to current address
+	if (rn == 5)
+	{
+		*v1 -= as -> addr;
+		
+		// we have a slight problem here
+		// PCR based on current insn loc is really
+		// -125 <= offset <= +130 (8 bit offset)
+		if (f8 || (!f16 && *v1 >= -125 && *v1 <= 130))
+		{
+			*opmode = OPER_INDEX8;
+			*postbyte = indir | 0x8C;
+			*v1 -= 3;
+			if (*v1 < -128 || *v1 > 127)
+				errorp2(ERR_OVERFLOW);
+			return 0;
+		}
+		
+		// anything else is 16 bit offset
+		// need 16 bit
+		*opmode = OPER_INDEX16;
+		*postbyte = indir | 0x8D;
+		*v1 -= 4;
+		return 0;
+	}
+
+	// constant offset from PC
+	if (rn == 6)
+	{
+		if (f8 || (!f16 && *v1 >= -128 && *v1 <= 127))
+		{
+			*opmode = OPER_INDEX8;
+			*postbyte = indir | 0x8C;
+			if (*v1 < -128 || *v1 > 127)
+				errorp2(ERR_OVERFLOW);
+			return 0;
+		}
+		
+		// everything else must be 16 bit
+		// need 16 bit
+		*opmode = OPER_INDEX16;
+		*postbyte = indir | 0x8D;
+		return 0;
+		
+	}
+
+	// we only have to deal with x,y,u,s here
+	if (!f8 && !f16 && *v1 >= -16 && *v1 <= 15)
+	{
+		if (*v1 == 0 && !f0 && !(as -> pragmas & PRAGMA_NOINDEX0TONONE))
+		{
+			*postbyte = rn << 5 | indir | 0x80 | 0x04;
+			*opmode = OPER_INDEX;
+			return 0;
+		}
+		// we pick the smallest value here
+		if (indir)
+		{
+			f8 = 1;
+			goto no5bit;
+		}
+		*postbyte = rn << 5 | (*v1 & 0x1F);
+		*opmode = OPER_INDEX5;
+		return 0;
+	}
+no5bit:
+	if (f16 || (!f8 && (*v1 < -128 || *v1 > 127)))
+	{
+		// must be a 16 bit offset here
+		*postbyte = rn << 5 | indir | 0x80 | 0x09;
+		*opmode = OPER_INDEX16;
+		return 0;
+	}
+	
+	// if we're here, we have an 8 bit offset
+	*postbyte = rn << 5 | indir | 0x80 | 0x08;
+	*opmode = OPER_INDEX8;
+	if (*v1 < -128 || *v1 > 127)
+		errorp2(ERR_OVERFLOW);
+	return 0;
+reterr:
+	*postbyte = -1;
+	*opmode = OPER_INDEX;
+	return -2;
+}
+
+void insn_indexed_aux(asmstate_t *as, sourceline_t *cl, char **optr, int *b1, int *b2, int *b3)
+{
+	int rval;
+	int v1, pb = -1;
+
+	*b1 = *b2 = *b3 = -1;
+
+	rval = parse_index_expr(as, cl, optr, &pb, &(cl -> addrmode), &v1);
+	if (rval < 0)
+		errorp1(ERR_BADOPER);
+	*b1 = pb;
+
+	if (cl -> addrmode == OPER_INDEX8)
+	{
+		*b2 = v1 & 0xff;
+	}
+	else if (cl -> addrmode == OPER_INDEX16 || cl -> addrmode == OPER_EXTIND)
+	{
+		*b2 = (v1 & 0xffff) >> 8;
+		*b3 = v1 & 0xff;
+	}
+}
+
+void insn_indexed(asmstate_t *as, sourceline_t *cl, char **optr)
+{
+	int b1, b2, b3;
+	
+	emitop(instab[cl -> opcode].ops[0]);
+	insn_indexed_aux(as, cl, optr, &b1, &b2, &b3);
+	if (b1 != -1)
+		emit(b1);
+	if (b2 != -1)
+		emit(b2);
+	if (b3 != -1)
+		emit(b3);
+}
+