--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/insn_indexed.c	Fri Jan 02 04:22:39 2009 +0000
@@ -0,0 +1,339 @@
+/*
+insn_indexed.c
+Copyright © 2008 William Astle
+
+This file is part of LWASM.
+
+LWASM 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/>.
+*/
+
+/*
+for handling indexed mode instructions
+*/
+
+#define __insn_indexed_c_seen__
+
+#include <ctype.h>
+#include <string.h>
+
+#include "lwasm.h"
+#include "instab.h"
+#include "expr.h"
+
+void insn_indexed_aux(asmstate_t *as, lwasm_line_t *l, const char **p, int *b1, int *b2, int *b3)
+{
+	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;
+ 	const char *p2;
+ 	lwasm_expr_stack_t *s;
+ 	
+	*b1 = *b2 = *b3 = -1;
+	
+	for (i = 0; i < 24; i++)
+	{
+		if (*((*p) + i) && !isspace(*((*p) + i)))
+			stbuf[i] = *((*p) + i);
+		else
+			break;
+	}
+	stbuf[i] = '\0';
+	if (!*((*p) + i) || isspace(*((*p) + 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])
+		{
+			*b1 = simpleindex[j].pb;
+			(*p) += i;
+			return;
+		}
+	}
+	
+	// now we have the hard ones to work out here
+	
+	// if we've previously forced the sizes, make a note of it
+	if (l -> fsize == 1)
+		f8 = 1;
+	else if (l -> fsize == 2)
+		f16 = 1;
+	
+	if (**p == '[')
+	{
+		indir = 1;
+		(*p)++;
+	}
+	
+	rn = 0;
+	for (i = 0; (*p)[i] && !isspace((*p)[i]); i++)
+	{
+		if ((*p)[i] == ',')
+		{
+			rn = 1;
+			break;
+		}
+	}
+		
+	if (!rn && indir)
+	{
+		// extended indir
+		*b1 = 0x9f;
+		*b2 = 0;
+		*b3 = 0;
+		s = lwasm_expr_eval(*p, &p2);
+		if (!s)
+		{
+			register_error(as, l, 1, "Bad expression");
+			return;
+		}
+		*p = p2;
+		if (**p != ']')
+		{
+			register_error(as, l, 1, "Bad operand");
+			return;
+		}
+		(*p)++;
+		if (!lwasm_expr_is_constant(s))
+		{
+			register_error(as, l, 2, "Incomplete reference");
+		}
+		rn = lwasm_expr_get_value(s);
+		lwasm_expr_stack_free(s);
+		*b2 = (rn >> 8) & 0xff;
+		*b3 = rn & 0xff;
+		return;
+	}
+
+	if (**p == '<')
+	{
+		f8 = 1;
+		(*p)++;
+	}
+	else if (**p == '>')
+	{
+		f16 = 1;
+		(*p)++;
+	}
+
+	if (**p == '0' && *(*p+1) == ',')
+	{
+		f0 = 1;
+	}
+	
+	// now we have to evaluate the expression
+	s = lwasm_expr_eval(*p, &p2);
+	*p = p2;
+	if (!s)
+	{
+		register_error(as, l, 1, "Bad expression");
+		return;
+	}
+	if (!lwasm_expr_is_constant(s))
+	{
+		register_error(as, l, 2, "Incomplete reference");
+		if (!f8 && !f0)
+		{
+			f16 = 1;
+			l -> fsize = 2;
+		}
+	}
+	rval = lwasm_expr_get_value(s);
+	lwasm_expr_stack_free(s);
+	
+	// now look for a comma; if not present, explode
+	if (*(*p)++ != ',')
+	{
+		// syntax error; force 0 bit
+		*b1 = 00;
+		return;
+	}
+	
+	// now get the register
+	rn = lwasm_lookupreg3(regs, p);
+	if (rn < 0)
+		goto reterr;
+
+	if (indir)
+	{
+		if (**p != ']')
+			goto reterr;
+		else
+			(*p)++;
+	}
+	
+	// nnnn,W is only 16 bit
+	if (rn == 4)
+	{
+		if (f8)
+			goto reterr;
+		if (!f16 && !f0 && !(as -> pragmas & PRAGMA_NOINDEX0TONONE) && rval == 0)
+		{
+			if (indir)
+				*b1 = 0x90;
+			else
+				*b1 = 0x8f;
+			return;
+		}
+		if (indir)
+			*b1 = 0xb0;
+		else
+			*b1 = 0xcf;
+		*b2 = (rval >> 8) & 0xff;
+		*b3 = rval & 0xff;
+		return;
+	}
+	
+	if (indir) indir = 0x10;
+	
+	// PCR? redo v1, v2 relative to current address
+	if (rn == 5)
+	{
+		rval -= as -> addr;
+		
+		// we have a slight problem here
+		// PCR based on current insn loc is really
+		// -125 <= offset <= +130 (8 bit offset)
+		// NOTE: when we are called, we already have the opcode emitted
+		// so we only need to worry about the size of the operand
+		// hence the 2 and 3 magic numbers below instead of 3 and 4
+		// (and that also avoids errors with two byte opcodes, etc)
+		if (f8 || (!f16 && rval >= -125 && rval <= 130))
+		{
+			*b1 = indir | 0x8C;
+			rval -= 2;
+			if (rval < -128 || rval > 127)
+				register_error(as, l, 2, "Byte overflow");
+			*b2 = rval & 0xff;
+			return;
+		}
+		
+		// anything else is 16 bit offset
+		// need 16 bit
+		*b1 = indir | 0x8D;
+		rval -= 3;
+		*b2 = (rval >> 8) & 0xff;
+		*b3 = rval & 0xff;
+		return;
+	}
+
+	// constant offset from PC
+	if (rn == 6)
+	{
+		if (f8 || (!f16 && rval >= -128 && rval <= 127))
+		{
+			*b1 = indir | 0x8C;
+			if (rval < -128 || rval > 127)
+				register_error(as, l, 2, "Byte overflow");
+			*b2 = rval & 0xff;
+			return;
+		}
+		
+		// everything else must be 16 bit
+		// need 16 bit
+		*b1 = indir | 0x8D;
+		*b2 = (rval >> 8) & 0xff;
+		*b3 = rval & 0xff;
+		return;
+	}
+
+	// we only have to deal with x,y,u,s here
+	if (!f8 && !f16 && rval >= -16 && rval <= 15)
+	{
+		if (rval == 0 && !f0 && !(as -> pragmas & PRAGMA_NOINDEX0TONONE))
+		{
+			*b1 = rn << 5 | indir | 0x80 | 0x04;
+			return;
+		}
+		// we pick the smallest value here
+		if (indir)
+		{
+			f8 = 1;
+			goto no5bit;
+		}
+		*b1 = rn << 5 | (rval & 0x1F);
+		return;
+	}
+no5bit:
+	if (f16 || (!f8 && (rval < -128 || rval > 127)))
+	{
+		// must be a 16 bit offset here
+		*b1 = rn << 5 | indir | 0x80 | 0x09;
+		*b2 = (rval >> 8) & 0xff;
+		*b3 = rval & 0xff;
+		return;
+	}
+	
+	// if we're here, we have an 8 bit offset
+	*b1 = rn << 5 | indir | 0x80 | 0x08;
+	if (rval < -128 || rval > 127)
+		register_error(as, l, 2, "Byte overflow");
+	*b2 = rval & 0xff;
+	return;
+reterr:
+	*b1 = 0;
+	return;
+}
+
+OPFUNC(insn_indexed)
+{
+	int b1, b2, b3;
+	
+	lwasm_emitop(as, l, instab[opnum].ops[0]);
+
+	insn_indexed_aux(as, l, (const char **)p, &b1, &b2, &b3);
+	if (b1 != -1)
+		lwasm_emit(as, l, b1);
+	if (b2 != -1)
+		lwasm_emit(as, l, b2);
+	if (b3 != -1)
+		lwasm_emit(as, l, b3);
+}