--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/lwasm/output.c	Wed Jan 19 22:27:17 2011 -0700
@@ -0,0 +1,593 @@
+/*
+output.c
+Copyright © 2009, 2010 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/>.
+
+
+Contains the code for actually outputting the assembled code
+*/
+#include <errno.h>
+#include <stdio.h>
+#include <string.h>
+#include <unistd.h>
+
+#include <lw_alloc.h>
+#include <lw_expr.h>
+
+#include "lwasm.h"
+
+void write_code_raw(asmstate_t *as, FILE *of);
+void write_code_decb(asmstate_t *as, FILE *of);
+void write_code_rawrel(asmstate_t *as, FILE *of);
+void write_code_obj(asmstate_t *as, FILE *of);
+void write_code_os9(asmstate_t *as, FILE *of);
+
+// this prevents warnings about not using the return value of fwrite()
+#define writebytes(s, l, c, f)	do { int r; r = fwrite((s), (l), (c), (f)); } while (0)
+
+void do_output(asmstate_t *as)
+{
+	FILE *of;
+	
+	if (as -> errorcount > 0)
+	{
+		fprintf(stderr, "Not doing output due to assembly errors.\n");
+		return;
+	}
+	
+	of = fopen(as -> output_file, "wb");
+	if (!of)
+	{
+		fprintf(stderr, "Cannot open '%s' for output", as -> output_file);
+		perror("");
+		return;
+	}
+
+	switch (as -> output_format)
+	{
+	case OUTPUT_RAW:
+		write_code_raw(as, of);
+		break;
+		
+	case OUTPUT_DECB:
+		write_code_decb(as, of);
+		break;
+		
+	case OUTPUT_RAWREL:
+		write_code_rawrel(as, of);
+		break;
+	
+	case OUTPUT_OBJ:
+		write_code_obj(as, of);
+		break;
+
+	case OUTPUT_OS9:
+		write_code_os9(as, of);
+		break;
+
+	default:
+		fprintf(stderr, "BUG: unrecognized output format when generating output file\n");
+		fclose(of);
+		unlink(as -> output_file);
+		return;
+	}
+
+	fclose(of);
+}
+
+/*
+rawrel output treats an ORG directive as an offset from the start of the
+file. Undefined results will occur if an ORG directive moves the output
+pointer backward. This particular implementation uses "fseek" to handle
+ORG requests and to skip over RMBs.
+
+This simple brain damanged method simply does an fseek before outputting
+each instruction.
+*/
+void write_code_rawrel(asmstate_t *as, FILE *of)
+{
+	line_t *cl;
+	
+	for (cl = as -> line_head; cl; cl = cl -> next)
+	{
+		if (cl -> outputl <= 0)
+			continue;
+		
+		fseek(of, lw_expr_intval(cl -> addr), SEEK_SET);
+		writebytes(cl -> output, cl -> outputl, 1, of);
+	}
+}
+
+/*
+raw merely writes all the bytes directly to the file as is. ORG is just a
+reference for the assembler to handle absolute references. Multiple ORG
+statements will produce mostly useless results
+*/
+void write_code_raw(asmstate_t *as, FILE *of)
+{
+	line_t *cl;
+	
+	for (cl = as -> line_head; cl; cl = cl -> next)
+	{
+		if (cl -> len > 0 && cl -> outputl == 0)
+		{
+			int i;
+			for (i = 0; i < cl -> len; i++)
+				writebytes("\0", 1, 1, of);
+			continue;
+		}
+		else if (cl -> outputl > 0)
+			writebytes(cl -> output, cl -> outputl, 1, of);
+	}
+}
+
+
+/*
+OS9 target also just writes all the bytes in order. No need for anything
+else.
+*/
+void write_code_os9(asmstate_t *as, FILE *of)
+{
+	line_t *cl;
+	
+	for (cl = as -> line_head; cl; cl = cl -> next)
+	{
+		if (cl -> inmod == 0)
+			continue;
+		if (cl -> len > 0 && cl -> outputl == 0)
+		{
+			int i;
+			for (i = 0; i < cl -> len; i++)
+				writebytes("\0", 1, 1, of);
+			continue;
+		}
+		else if (cl -> outputl > 0)
+			writebytes(cl -> output, cl -> outputl, 1, of);
+	}
+}
+
+void write_code_decb(asmstate_t *as, FILE *of)
+{
+	long preambloc;
+	line_t *cl;
+	int blocklen = -1;
+	int nextcalc = -1;
+	unsigned char outbuf[5];
+	int caddr;
+	
+	for (cl = as -> line_head; cl; cl = cl -> next)
+	{
+		if (cl -> outputl < 0)
+			continue;
+		caddr = lw_expr_intval(cl -> addr);
+		if (caddr != nextcalc && cl -> outputl > 0)
+		{
+			// need preamble here
+			if (blocklen > 0)
+			{
+				// update previous preamble if needed
+				fseek(of, preambloc, SEEK_SET);
+				outbuf[0] = (blocklen >> 8) & 0xFF;
+				outbuf[1] = blocklen & 0xFF;
+				writebytes(outbuf, 2, 1, of);
+				fseek(of, 0, SEEK_END);
+			}
+			blocklen = 0;
+			nextcalc = caddr;
+			outbuf[0] = 0x00;
+			outbuf[1] = 0x00;
+			outbuf[2] = 0x00;
+			outbuf[3] = (nextcalc >> 8) & 0xFF;
+			outbuf[4] = nextcalc & 0xFF;
+			preambloc = ftell(of) + 1;
+			writebytes(outbuf, 5, 1, of);
+		}
+		nextcalc += cl -> outputl;
+		writebytes(cl -> output, cl -> outputl, 1, of);
+		blocklen += cl -> outputl;
+	}
+	if (blocklen > 0)
+	{
+		fseek(of, preambloc, SEEK_SET);
+		outbuf[0] = (blocklen >> 8) & 0xFF;
+		outbuf[1] = blocklen & 0xFF;
+		writebytes(outbuf, 2, 1, of);
+		fseek(of, 0, SEEK_END);
+	}
+	
+	// now write postamble
+	outbuf[0] = 0xFF;
+	outbuf[1] = 0x00;
+	outbuf[2] = 0x00;
+	outbuf[3] = (as -> execaddr >> 8) & 0xFF;
+	outbuf[4] = (as -> execaddr) & 0xFF;
+	writebytes(outbuf, 5, 1, of);
+}
+
+void write_code_obj_sbadd(sectiontab_t *s, unsigned char b)
+{
+	if (s -> oblen >= s -> obsize)
+	{
+		s -> obytes = lw_realloc(s -> obytes, s -> obsize + 128);
+		s -> obsize += 128;
+	}
+	s -> obytes[s -> oblen] = b;
+	s -> oblen += 1;
+}
+
+
+int write_code_obj_expraux(lw_expr_t e, void *of)
+{
+	int tt;
+	int v;
+	unsigned char buf[16];
+	
+	tt = lw_expr_type(e);
+
+	switch (tt)
+	{
+	case lw_expr_type_oper:
+		buf[0] =  0x04;
+		switch (lw_expr_whichop(e))
+		{
+		case lw_expr_oper_plus:
+			buf[1] = 0x01;
+			break;
+		
+		case lw_expr_oper_minus:
+			buf[1] = 0x02;
+			break;
+		
+		case lw_expr_oper_times:
+			buf[1] = 0x03;
+			break;
+		
+		case lw_expr_oper_divide:
+			buf[1] = 0x04;
+			break;
+		
+		case lw_expr_oper_mod:
+			buf[1] = 0x05;
+			break;
+		
+		case lw_expr_oper_intdiv:
+			buf[1] = 0x06;
+			break;
+		
+		case lw_expr_oper_bwand:
+			buf[1] = 0x07;
+			break;
+		
+		case lw_expr_oper_bwor:
+			buf[1] = 0x08;
+			break;
+		
+		case lw_expr_oper_bwxor:
+			buf[1] = 0x09;
+			break;
+		
+		case lw_expr_oper_and:
+			buf[1] = 0x0A;
+			break;
+		
+		case lw_expr_oper_or:
+			buf[1] = 0x0B;
+			break;
+		
+		case lw_expr_oper_neg:
+			buf[1] = 0x0C;
+			break;
+		
+		case lw_expr_oper_com:
+			buf[1] = 0x0D;
+			break;
+
+		default:
+			buf[1] = 0xff;
+		}
+		writebytes(buf, 2, 1, of);
+		return 0;
+
+	case lw_expr_type_int:
+		v = lw_expr_intval(e);
+		buf[0] = 0x01;
+		buf[1] = (v >> 8) & 0xff;
+		buf[2] = v & 0xff;
+		writebytes(buf, 3, 1, of);
+		return 0;
+		
+	case lw_expr_type_special:
+		v = lw_expr_specint(e);
+		switch (v)
+		{
+		case lwasm_expr_secbase:
+			{
+				// replaced with a synthetic symbol
+				sectiontab_t *se;
+				se = lw_expr_specptr(e);
+				
+				writebytes("\x03\x02", 2, 1, of);
+				writebytes(se -> name, strlen(se -> name) + 1, 1, of);
+				return 0;
+			}	
+		case lwasm_expr_import:
+			{
+				importlist_t *ie;
+				ie = lw_expr_specptr(e);
+				buf[0] = 0x02;
+				writebytes(buf, 1, 1, of);
+				writebytes(ie -> symbol, strlen(ie -> symbol) + 1, 1, of);
+				return 0;
+			}
+		case lwasm_expr_syment:
+			{
+				struct symtabe *se;
+				se = lw_expr_specptr(e);
+				buf[0] = 0x03;
+				writebytes(buf, 1, 1, of);
+				writebytes(se -> symbol, strlen(se -> symbol), 1, of);
+				if (se -> context != -1)
+				{
+					sprintf(buf, "\x01%d", se -> context);
+					writebytes(buf, strlen(buf), 1, of);
+				}
+				writebytes("", 1, 1, of);
+				return 0;
+			}
+		}
+			
+	default:
+		// unrecognized term type - replace with integer 0
+//		fprintf(stderr, "Unrecognized term type: %s\n", lw_expr_print(e));
+		buf[0] = 0x01;
+		buf[1] = 0x00;
+		buf[2] = 0x00;
+		writebytes(buf, 3, 1, of);
+		break;
+	}
+	return 0;
+}
+
+
+void write_code_obj(asmstate_t *as, FILE *of)
+{
+	line_t *l;
+	sectiontab_t *s;
+	reloctab_t *re;
+	exportlist_t *ex;
+	struct symtabe *se;
+
+	int i;
+	unsigned char buf[16];
+
+	// output the magic number and file header
+	// the 8 is NOT an error
+	writebytes("LWOBJ16", 8, 1, of);
+	
+	// run through the entire system and build the byte streams for each
+	// section; at the same time, generate a list of "local" symbols to
+	// output for each section
+	// NOTE: for "local" symbols, we will append \x01 and the ascii string
+	// of the context identifier (so sym in context 1 would be "sym\x011"
+	// we can do this because the linker can handle symbols with any
+	// character other than NUL.
+	// also we will generate a list of incomplete references for each
+	// section along with the actual definition that will be output
+	
+	// once all this information is generated, we will output each section
+	// to the file
+	
+	// NOTE: we build everything in memory then output it because the
+	// assembler accepts multiple instances of the same section but the
+	// linker expects only one instance of each section in the object file
+	// so we need to collect all the various pieces of a section together
+	// (also, the assembler treated multiple instances of the same section
+	// as continuations of previous sections so we would need to collect
+	// them together anyway.
+	
+	for (l = as -> line_head; l; l = l -> next)
+	{
+		if (l -> csect)
+		{
+			// we're in a section - need to output some bytes
+			if (l -> outputl > 0)
+				for (i = 0; i < l -> outputl; i++)
+					write_code_obj_sbadd(l -> csect, l -> output[i]);
+			else if (l -> outputl == 0 || l -> outputl == -1)
+				for (i = 0; i < l -> len; i++)
+					write_code_obj_sbadd(l -> csect, 0);
+		}
+	}
+	
+	// run through the sections
+	for (s = as -> sections; s; s = s -> next)
+	{
+		// write the name
+		writebytes(s -> name, strlen(s -> name) + 1, 1, of);
+		
+		// write the flags
+		if (s -> flags & section_flag_bss)
+			writebytes("\x01", 1, 1, of);
+		
+		// indicate end of flags - the "" is NOT an error
+		writebytes("", 1, 1, of);
+		
+		// now the local symbols
+		
+		// a symbol for section base address
+		writebytes("\x02", 1, 1, of);
+		writebytes(s -> name, strlen(s -> name) + 1, 1, of);
+		// address 0; "\0" is not an error
+		writebytes("\0", 2, 1, of);
+		for (se = as -> symtab.head; se; se = se -> next)
+		{
+			lw_expr_t te;
+			
+			debug_message(as, 200, "Consider symbol %s (%p) for export in section %p", se -> symbol, se -> section, s);
+			
+			// ignore symbols not in this section
+			if (se -> section != s)
+				continue;
+			
+			debug_message(as, 200, "  In section");
+			
+			if (se -> flags & symbol_flag_set)
+				continue;
+			
+			debug_message(as, 200, "  Not symbol_flag_set");
+			
+			te = lw_expr_copy(se -> value);
+			debug_message(as, 200, "  Value=%s", lw_expr_print(te));
+			as -> exportcheck = 1;
+			as -> csect = s;
+			lwasm_reduce_expr(as, te);
+			as -> exportcheck = 0;
+
+			debug_message(as, 200, "  Value2=%s", lw_expr_print(te));
+			
+			// don't output non-constant symbols
+			if (!lw_expr_istype(te, lw_expr_type_int))
+			{
+				lw_expr_destroy(te);
+				continue;
+			}
+
+			writebytes(se -> symbol, strlen(se -> symbol), 1, of);
+			if (se -> context >= 0)
+			{
+				writebytes("\x01", 1, 1, of);
+				sprintf(buf, "%d", se -> context);
+				writebytes(buf, strlen(buf), 1, of);
+			}
+			// the "" is NOT an error
+			writebytes("", 1, 1, of);
+			
+			// write the address
+			buf[0] = (lw_expr_intval(te) >> 8) & 0xff;
+			buf[1] = lw_expr_intval(te) & 0xff;
+			writebytes(buf, 2, 1, of);
+			lw_expr_destroy(te);
+		}	
+		// flag end of local symbol table - "" is NOT an error
+		writebytes("", 1, 1, of);
+		
+		// now the exports -- FIXME
+		for (ex = as -> exportlist; ex; ex = ex -> next)
+		{
+			int eval;
+			lw_expr_t te;
+			line_t tl;
+			
+			if (ex -> se == NULL)
+				continue;
+			if (ex -> se -> section != s)
+				continue;
+			te = lw_expr_copy(ex -> se -> value);
+			as -> csect = ex -> se -> section;
+			as -> exportcheck = 1;
+			tl.as = as;
+			as -> cl = &tl;
+			lwasm_reduce_expr(as, te);
+			as -> exportcheck = 0;
+			as -> cl = NULL;
+			if (!lw_expr_istype(te, lw_expr_type_int))
+			{
+				lw_expr_destroy(te);
+				continue;
+			}
+			eval = lw_expr_intval(te);
+			lw_expr_destroy(te);
+			writebytes(ex -> symbol, strlen(ex -> symbol) + 1, 1, of);
+			buf[0] = (eval >> 8) & 0xff;
+			buf[1] = eval & 0xff;
+			writebytes(buf, 2, 1, of);
+		}
+	
+		// flag end of exported symbols - "" is NOT an error
+		writebytes("", 1, 1, of);
+		
+		// FIXME - relocation table
+		for (re = s -> reloctab; re; re = re -> next)
+		{
+			int offset;
+			lw_expr_t te;
+			line_t tl;
+			
+			tl.as = as;
+			as -> cl = &tl;
+			as -> csect = s;
+			as -> exportcheck = 1;
+			
+			if (re -> expr == NULL)
+			{
+				// this is an error but we'll simply ignore it
+				// and not output this expression
+				continue;
+			}
+			
+			// work through each term in the expression and output
+			// the proper equivalent to the object file
+			if (re -> size == 1)
+			{
+				// flag an 8 bit relocation (low 8 bits will be used)
+				buf[0] = 0xFF;
+				buf[1] = 0x01;
+				writebytes(buf, 2, 1, of);
+			}
+			
+			te = lw_expr_copy(re -> offset);
+			lwasm_reduce_expr(as, te);
+			if (!lw_expr_istype(te, lw_expr_type_int))
+			{
+				lw_expr_destroy(te);
+				continue;
+			}
+			offset = lw_expr_intval(te);
+			lw_expr_destroy(te);
+			
+			// output expression
+			lw_expr_testterms(re -> expr, write_code_obj_expraux, of);
+			
+			// flag end of expressions
+			writebytes("", 1, 1, of);
+			
+			// write the offset
+			buf[0] = (offset >> 8) & 0xff;
+			buf[1] = offset & 0xff;
+			writebytes(buf, 2, 1, of);
+		}
+
+		// flag end of incomplete references list
+		writebytes("", 1, 1, of);
+		
+		// now blast out the code
+		
+		// length
+		buf[0] = s -> oblen >> 8 & 0xff;
+		buf[1] = s -> oblen & 0xff;
+		writebytes(buf, 2, 1, of);
+		
+		if (!(s -> flags & section_flag_bss))
+		{
+			writebytes(s -> obytes, s -> oblen, 1, of);
+		}
+	}
+	
+	// flag no more sections
+	// the "" is NOT an error
+	writebytes("", 1, 1, of);
+}