view lwasm/insn_indexed.c @ 481:62720ac9e28d

Exclude extended indirect from operandsizewarning pragma Constant indirect addressing is only available in "extended" variety (16 bits) so make sure no warning appears when plain extended indirect addressing is used.
author William Astle <lost@l-w.ca>
date Wed, 12 Dec 2018 21:18:20 -0700
parents 2c1c5dd84024
children
line wrap: on
line source
/*
insn_indexed.c
Copyright © 2009 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
*/

#include <ctype.h>
#include <string.h>

#include <lw_expr.h>

#include "lwasm.h"
#include "instab.h"

/*
l -> lint: size of operand (0, 1, 2, -1 if not determined)
l -> pb: actual post byte (from "resolve" stage) or info passed
	forward to the resolve stage (if l -> line is -1); 0x80 is indir
	bits 0-2 are register number
*/
void insn_parse_indexed_aux(asmstate_t *as, line_t *l, char **p)
{
	static const char *regs9 = "X  Y  U  S     PCRPC ";
	static const char *regs  = "X  Y  U  S  W  PCRPC ";
	int i, rn;
	int indir = 0;
	int f0 = 0;
	const char *reglist;
	lw_expr_t e;
	char *tstr;
	

	if (CURPRAGMA(l, PRAGMA_6809))
	{
		reglist = regs9;
	}
	else
	{
		reglist = regs;
	}
	// is it indirect?
	if (**p == '[')
	{
		indir = 1;
		(*p)++;
	}
	lwasm_skip_to_next_token(l, p);
	if (**p == ',')
	{
		int incdec = 0;
		/* we have a pre-dec, post-inc, or no offset mode here */
		(*p)++;
		lwasm_skip_to_next_token(l, p);
		if (**p == '-')
		{
			incdec = -1;
			(*p)++;
			if (**p == '-')
			{
				incdec = -2;
				(*p)++;
			}
			lwasm_skip_to_next_token(l, p);
		}
		/* allowed registers: X, Y, U, S, or W (6309) */
		switch (**p)
		{
		case 'x':
		case 'X':
			rn = 0;
			break;
		
		case 'y':
		case 'Y':
			rn = 1;
			break;
			
		case 'u':
		case 'U':
			rn = 2;
			break;
			
		case 's':
		case 'S':
			rn = 3;
			break;
			
		case 'w':
		case 'W':
			if (CURPRAGMA(l, PRAGMA_6809))
			{
				lwasm_register_error(as, l, E_OPERAND_BAD);
				return;
			}
			rn = 4;
			break;
			
		default:
			lwasm_register_error(as, l, E_OPERAND_BAD);
			return;
		}
		(*p)++;
		lwasm_skip_to_next_token(l, p);
		if (**p == '+')
		{
			if (incdec != 0)
			{
				lwasm_register_error(as, l, E_OPERAND_BAD);
				return;
			}
			incdec = 1;
			(*p)++;
			if (**p == '+')
			{
				incdec = 2;
				(*p)++;
			}
			lwasm_skip_to_next_token(l, p);
		}
		if (indir)
		{
			if (**p != ']')
			{
				lwasm_register_error(as, l, E_OPERAND_BAD);
				return;
			}
			(*p)++;
		}
		if (indir || rn == 4)
		{
			if (incdec == 1 || incdec == -1)
			{
				lwasm_register_error(as, l, E_OPERAND_BAD);
				return;
			}
		}
		if (rn == 4)
		{
			if (indir)
			{
				if (incdec == 0)
					i = 0x90;
				else if (incdec == -2)
					i = 0xF0;
				else
					i = 0xD0;
			}
			else
			{
				if (incdec == 0)
					i = 0x8F;
				else if (incdec == -2)
					i = 0xEF;
				else
					i = 0xCF;
			}
		}
		else
		{
			switch (incdec)
			{
			case 0:
				i = 0x84;
				break;
			case 1:
				i = 0x80;
				break;
			case 2:
				i = 0x81;
				break;
			case -1:
				i = 0x82;
				break;
			case -2:
				i = 0x83;
				break;
			}
			i = (rn << 5) | i | (indir << 4);
		}
		l -> pb = i;
		l -> lint = 0;
		return;
	}
	i = toupper(**p);
	if (
			(i == 'A' || i == 'B' || i == 'D') ||
			(!CURPRAGMA(l, PRAGMA_6809) && (i == 'E' || i == 'F' || i == 'W'))
	   )
	{
		tstr = *p + 1;
		lwasm_skip_to_next_token(l, &tstr);
		if (*tstr == ',')
		{
			*p = tstr + 1;
			lwasm_skip_to_next_token(l, p);
			switch (**p)
			{
			case 'x':
			case 'X':
				rn = 0;
				break;
		
			case 'y':
			case 'Y':
				rn = 1;
				break;
			
			case 'u':
			case 'U':
				rn = 2;
				break;
			
			case 's':
			case 'S':
				rn = 3;
				break;
			
			default:
				lwasm_register_error(as, l, E_OPERAND_BAD);
				return;
			}
			(*p)++;
			lwasm_skip_to_next_token(l, p);
			if (indir)
			{
				if (**p != ']')
				{
					lwasm_register_error(as, l, E_OPERAND_BAD);
					return;
				}
				(*p)++;
			}
			
			switch (i)
			{
			case 'A':
				i = 0x86;
				break;
			
			case 'B':
				i = 0x85;
				break;
			
			case 'D':
				i = 0x8B;
				break;
			
			case 'E':
				i = 0x87;
				break;
			
			case 'F':
				i = 0x8A;
				break;
			
			case 'W':
				i = 0x8E;
				break;
			}
			l -> pb = i | (indir << 4) | (rn << 5);
			l -> lint = 0;
			return;
		}
	}
	
	/* we have the "expression" types now */
	if (**p == '<')
	{
		l -> lint = 1;
		(*p)++;
		if (**p == '<')
		{
			l -> lint = 3;
			(*p)++;
			if (indir)
			{
				lwasm_register_error(as, l, E_ILL5);
				return;
			}
		}
	}
	else if (**p == '>')
	{
		l -> lint = 2;
		(*p)++;
	}
	lwasm_skip_to_next_token(l, p);
	if (**p == '0')
	{
		tstr = *p + 1;
		lwasm_skip_to_next_token(l, &tstr);
		if (*tstr == ',')
		{
			f0 = 1;
		}
	}

	// now we have to evaluate the expression
	e = lwasm_parse_expr(as, p);
	if (!e)
	{
		lwasm_register_error(as, l, E_OPERAND_BAD);
		return;
	}
	lwasm_save_expr(l, 0, e);
	
	if (**p != ',')
	{
		/* if no comma, we have extended indirect */
		if (l -> lint == 1 || **p != ']')
		{
			lwasm_register_error(as, l, E_OPERAND_BAD);
			return;
		}
		(*p)++;
		l -> lint = 2;
		l -> pb = 0x9F;
		return;
	}
	(*p)++;
	lwasm_skip_to_next_token(l, p);
	// now get the register
	rn = lwasm_lookupreg3(reglist, p);
	if (rn < 0)
	{
		lwasm_register_error(as, l, E_REGISTER_BAD);
		return;
	}
	
	if (indir)
	{
		if (**p != ']')
		{
			lwasm_register_error(as, l, E_OPERAND_BAD);
			return;
		}
		else
			(*p)++;
	}

	if (rn <= 3)
	{
		// X,Y,U,S
		if (l -> lint == 1)
		{
			l -> pb = 0x88 | (rn << 5) | (indir ? 0x10 : 0);
			return;
		}
		else if (l -> lint == 2)
		{
			l -> pb = 0x89 | (rn << 5) | (indir ? 0x10 : 0);
			return;
		}
		else if (l -> lint == 3)
		{
			l -> pb = (rn << 5);
		}
	}

	// nnnn,W is only 16 bit (or 0 bit)
	if (rn == 4)
	{
		if (l -> lint == 1)
		{
			lwasm_register_error(as, l, E_NW_8);
			return;
		}
		else if (l -> lint == 3)
		{
			lwasm_register_error(as, l, E_ILL5);
			return;
		}

		if (l -> lint == 2)
		{
			l -> pb = indir ? 0xb0 : 0xaf;
			l -> lint = 2;
			return;
		}
		
		l -> pb = (0x80 * indir) | rn;

/* [,w] and ,w
			if (indir)
				*b1 = 0x90;
			else
				*b1 = 0x8f;
*/
		return;
	}
	
	// PCR? then we have PC relative addressing (like B??, LB??)
	if (rn == 5 || (rn == 6 && CURPRAGMA(l, PRAGMA_PCASPCR)))
	{
		lw_expr_t e1, e2;
		// external references are handled exactly the same as for
		// relative addressing modes
		// on pass 1, adjust the expression for a subtraction of the
		// current address
		// e - (addr + linelen) => e - addr - linelen
		
		e2 = lw_expr_build(lw_expr_type_special, lwasm_expr_linelen, l);
		e1 = lw_expr_build(lw_expr_type_oper, lw_expr_oper_minus, e, e2);
		lw_expr_destroy(e2);
		e2 = lw_expr_build(lw_expr_type_oper, lw_expr_oper_minus, e1, l -> addr);
		lw_expr_destroy(e1);
		lwasm_save_expr(l, 0, e2);
		if (l -> lint == 1)
		{
			l -> pb = indir ? 0x9C : 0x8C;
			return;
		}
		else if (l -> lint == 2)
		{
			l -> pb = indir ? 0x9D : 0x8D;
			return;
		}
		else if (l -> lint == 3)
		{
			lwasm_register_error(as, l, E_ILL5);
			return;
		}
	}
	
	if (rn == 6)
	{
		if (l -> lint == 1)
		{
			l -> pb = indir ? 0x9C : 0x8C;
			return;
		}
		else if (l -> lint == 2)
		{
			l -> pb = indir ? 0x9D : 0x8D;
			return;
		}
		else if (l -> lint == 3)
		{
			lwasm_register_error(as, l, E_ILL5);
			return;
		}
	}

	if (l -> lint != 3)
		l -> pb = (indir * 0x80) | rn | (f0 * 0x40);
}

PARSEFUNC(insn_parse_indexed)
{
	l -> lint = -1;
	insn_parse_indexed_aux(as, l, p);

	if (l -> lint != -1)
	{
		if (l -> lint == 3)
			l -> len = OPLEN(instab[l -> insn].ops[0]) + 1;
		else
			l -> len = OPLEN(instab[l -> insn].ops[0]) + l -> lint + 1;
	}
}

void insn_resolve_indexed_aux(asmstate_t *as, line_t *l, int force, int elen)
{
	// here, we have an expression which needs to be
	// resolved; the post byte is determined here as well
	lw_expr_t e, e2;
	int pb = -1;
	int v;
	
	if (l -> len != -1)
		return;

	e = lwasm_fetch_expr(l, 0);
	if (!lw_expr_istype(e, lw_expr_type_int))
	{
		// temporarily set the instruction length to see if we get a
		// constant for our expression; if so, we can select an instruction
		// size
		e2 = lw_expr_copy(e);
		// magic 2 for 8 bit (post byte + offset)
		l -> len = OPLEN(instab[l -> insn].ops[0]) + elen + 2;
		lwasm_reduce_expr(as, e2);
//		l -> len += 1;
//		e3 = lw_expr_copy(e);
//		lwasm_reduce_expr(as, e3);
		l -> len = -1;
		if (lw_expr_istype(e2, lw_expr_type_int))
		{
			v = lw_expr_intval(e2);
			// we have a reducible expression here which depends on
			// the size of this instruction
			if (v == 0 && !CURPRAGMA(l, PRAGMA_NOINDEX0TONONE) && (l -> pb & 0x07) <= 4)
			{
				if ((l -> pb & 0x07) < 4)
				{
					pb = 0x84 | ((l -> pb & 0x03) << 5) | ((l -> pb & 0x80) ? 0x10 : 0);
				}
				else
				{
					pb = (l -> pb & 0x80) ? 0x90 : 0x8F;
				}
				l -> pb = pb;
				lw_expr_destroy(e2);
				l -> lint = 0;
				return;
			}
			else if (v < -128 || v > 127)
			{
				l -> lint = 2;
				switch (l -> pb & 0x07)
				{
				case 0:
				case 1:
				case 2:
				case 3:
					pb = 0x89 | ((l -> pb & 0x03) << 5) | ((l -> pb & 0x80) ? 0x10 : 0);
					break;
			
				case 4: // W
					pb = (l -> pb & 0x80) ? 0xB0 : 0xAF;
					break;
				
				case 5: // PCR
				case 6: // PC
					pb = (l -> pb & 0x80) ? 0x9D : 0x8D;
					break;
				}
				
				l -> pb = pb;
				lw_expr_destroy(e2);
//				lw_expr_destroy(e3);
				return;
			}
			else if ((l -> pb & 0x80) || ((l -> pb & 0x07) > 3) || v < -16 || v > 15)
			{
				// if not a 5 bit value, is indirect, or is not X,Y,U,S
				l -> lint = 1;
				switch (l -> pb & 0x07)
				{
				case 0:
				case 1:
				case 2:
				case 3:
					pb = 0x88 | ((l -> pb & 0x03) << 5) | ((l -> pb & 0x80) ? 0x10 : 0);
					break;
			
				case 4: // W
					// use 16 bit because W doesn't have 8 bit, unless 0
					if (v == 0 && !(CURPRAGMA(l, PRAGMA_NOINDEX0TONONE) || l -> pb & 0x40))
					{
						pb = (l -> pb & 0x80) ? 0x90 : 0x8F;
						l -> lint = 0;
					}
					else
					{
						pb = (l -> pb & 0x80) ? 0xB0 : 0xAF;
						l -> lint = 2;
					}
					break;
				
				case 5: // PCR
				case 6: // PC
					pb = (l -> pb & 0x80) ? 0x9C : 0x8C;
					break;
				}
			
				l -> pb = pb;
				lw_expr_destroy(e2);
				return;
			}
			else
			{
				// we have X,Y,U,S and a possible 5 bit here
				l -> lint = 0;
				
				if (v == 0 && !(CURPRAGMA(l, PRAGMA_NOINDEX0TONONE) || l -> pb & 0x40))
				{
					pb = (l -> pb & 0x03) << 5 | 0x84;
				}	
				else
				{
					pb = ((l -> pb & 0x03) << 5) | (v & 0x1F);
				}
				l -> pb = pb;
				lw_expr_destroy(e2);
				return;
			}
		}
		else
		{
			if ((l -> pb & 0x07) == 5 || (l -> pb & 0x07) == 6)
			{
				// NOTE: this will break in some particularly obscure corner cases
				// which are not likely to show up in normal code. Notably, if, for
				// some reason, the target gets *farther* away if shorter addressing
				// modes are chosen, which should only happen if the symbol is before
				// the instruction in the source file and there is some sort of ORG
				// statement or similar in between which forces the address of this
				// instruction, and the differences happen to cross the 8 bit boundary.
				// For this reason, we use a heuristic and allow a margin on the 8
				// bit boundary conditions.
				v = as -> pretendmax;
				as -> pretendmax = 1;
				lwasm_reduce_expr(as, e2);
				as -> pretendmax = v;
				if (lw_expr_istype(e2, lw_expr_type_int))
				{
					v = lw_expr_intval(e2);
					// Actual range is -128 <= offset <= 127; we're allowing a fudge
					// factor of 25 or so bytes so that we're less likely to accidentally
					// cross into the 16 bit boundary in weird corner cases.
					if (v >= -100 && v <= 100)
					{
						l -> lint = 1;
						l -> pb = (l -> pb & 0x80) ? 0x9C : 0x8C;
						return;
					}
				}
			}
		}
		lw_expr_destroy(e2);
	}
		
	if (lw_expr_istype(e, lw_expr_type_int))
	{
		// we know how big it is
		v = lw_expr_intval(e);
			
		if (v == 0 && !CURPRAGMA(l, PRAGMA_NOINDEX0TONONE) && (l -> pb & 0x07) <= 4 && ((l -> pb & 0x40) == 0))
		{
			if ((l -> pb & 0x07) < 4)
			{
				pb = 0x84 | ((l -> pb & 0x03) << 5) | ((l -> pb & 0x80) ? 0x10 : 0);
			}
			else
			{
				pb = (l -> pb & 0x80) ? 0x90 : 0x8F;
			}
			l -> pb = pb;
			l -> lint = 0;
			return;
		}
		else if (v < -128 || v > 127)
		{
		do16bit:
			l -> lint = 2;
			switch (l -> pb & 0x07)
			{
			case 0:
			case 1:
			case 2:
			case 3:
				pb = 0x89 | (l -> pb & 0x03) << 5 | ((l -> pb & 0x80) ? 0x10 : 0);
				break;
			
			case 4: // W
				pb = (l -> pb & 0x80) ? 0xB0 : 0xAF;
				break;
				
			case 5: // PCR
			case 6: // PC
				pb = (l -> pb & 0x80) ? 0x9D : 0x8D;
				break;
			}
			
			l -> pb = pb;
			return;
		}
		else if ((l -> pb & 0x80) || ((l -> pb & 0x07) > 3) || v < -16 || v > 15)
		{
			// if not a 5 bit value, is indirect, or is not X,Y,U,S
			l -> lint = 1;
			switch (l -> pb & 0x07)
			{
			case 0:
			case 1:
			case 2:
			case 3:
				pb = 0x88 | (l -> pb & 0x03) << 5 | ((l -> pb & 0x80) ? 0x10 : 0);
				break;
			
			case 4: // W
				// use 16 bit because W doesn't have 8 bit, unless 0
				if (v == 0 && !(CURPRAGMA(l, PRAGMA_NOINDEX0TONONE) || l -> pb & 0x40))
				{
					pb = (l -> pb & 0x80) ? 0x90 : 0x8F;
					l -> lint = 0;
				}
				else
				{
					pb = (l -> pb & 0x80) ? 0xB0 : 0xAF;
					l -> lint = 2;
				}
				break;
				
			case 5: // PCR
			case 6: // PC
				pb = (l -> pb & 0x80) ? 0x9C : 0x8C;
				break;
			}
			
			l -> pb = pb;
			return;
		}
		else
		{
			// we have X,Y,U,S and a possible 5 bit here
			l -> lint = 0;
			
			if (v == 0 && !(CURPRAGMA(l, PRAGMA_NOINDEX0TONONE) || l -> pb & 0x40))
			{
				pb = (l -> pb & 0x03) << 5 | 0x84;
			}
			else
			{
				pb = ((l -> pb & 0x03) << 5) | (v & 0x1F);
			}
			l -> pb = pb;
			return;
		}
	}
	else
	{
		// we don't know how big it is
		if (!force)
			return;
		// force 16 bit if we don't know
		l -> lint = 2;
		goto do16bit;
	}
}

RESOLVEFUNC(insn_resolve_indexed)
{
	if (l -> lint == -1)
		insn_resolve_indexed_aux(as, l, force, 0);
	
	if (l -> lint != -1 && l -> pb != -1)
	{
		if (l -> lint == 3)
			l -> len = OPLEN(instab[l -> insn].ops[0]) + 1;
		else
			l -> len = OPLEN(instab[l -> insn].ops[0]) + l -> lint + 1;
	}
}

void insn_emit_indexed_aux(asmstate_t *as, line_t *l)
{
	lw_expr_t e;
	
	if (l -> lint == 1)
	{
		int i;
		e = lwasm_fetch_expr(l, 0);
		i = lw_expr_intval(e);
		if (i < -128 || i > 127)
		{
			lwasm_register_error(as, l, E_BYTE_OVERFLOW);
		}
	}
	
	// exclude expr,W since that can only be 16 bits
	if (l -> lint == 3)
	{
		int offs;
		e = lwasm_fetch_expr(l, 0);
		if (lw_expr_istype(e, lw_expr_type_int))
		{
			offs = lw_expr_intval(e);
			if ((offs >= -16 && offs <= 15) || offs >= 0xFFF0)
			{
				l -> pb |= offs & 0x1f;
				l -> lint = 0;
			}
			else
			{
				lwasm_register_error(as, l, E_BYTE_OVERFLOW);
			}
		}
		else
		{
			lwasm_register_error(as, l, E_EXPRESSION_NOT_RESOLVED);
		}
	}
	// note that extended indirect (post byte 0x9f) can only be 16 bits
	else if (l -> lint == 2 && CURPRAGMA(l, PRAGMA_OPERANDSIZE) && (l -> pb != 0xAF && l -> pb != 0xB0 && l -> pb != 0x9f))
	{
		int offs;
		e = lwasm_fetch_expr(l, 0);
		if (lw_expr_istype(e, lw_expr_type_int))
		{
			offs = lw_expr_intval(e);
			if ((offs >= -128 && offs <= 127) || offs >= 0xFF80)
			{
				lwasm_register_error(as, l, W_OPERAND_SIZE);
			}
		}
	}
	
	lwasm_emitop(l, instab[l -> insn].ops[0]);
	lwasm_emitop(l, l -> pb);

	l -> cycle_adj = lwasm_cycle_calc_ind(l);

	if (l -> lint > 0)
	{
		e = lwasm_fetch_expr(l, 0);
		lwasm_emitexpr(l, e, l -> lint);
	}
}

EMITFUNC(insn_emit_indexed)
{
	insn_emit_indexed_aux(as, l);
}