Return to unasm.c CVS log

Up to [MW Coherent from dump] / coherent / b / bin / c / n2 / i8086

coherent

/*
 * The unassembler; this routine converts
 * the internal form of a machine instruction into
 * an intermediate form printable by cc3.  The output can
 * be made to look a lot like any assembler format by rewriting cc3.
 * This is the new VAX base, including
 * all edits up to revision 48.
 */
#ifdef   vax
#include "INC$LIB:cc2.h"
#else
#include "cc2.h"
#endif

unassemble(ip1)
register INS	*ip1;
{
	register INS	*ip2;
	register int	rel;
	register int	i, lab;
	register int	nlf;
	register int	opflag;

	switch (ip1->i_type) {

	case LLLINK:
		genone(ZWORD, A_LID|A_DIR, ip1->i_labno);
		break;

	case ENTER:
		genseg(ip1->i_seg);
		break;

	case ALIGN:
		bput(ALIGN); bput(0);
		break;

	case BLOCK:
		bput(BLOCK); zput(ip1->i_len);
		break;

	case LLABEL:
		bput(LLABEL); iput(ip1->i_labno);
		break;

	case JUMP:
		if ((rel=ip1->i_rel) == ZJMP) {
			genone(ZJMP, A_LID|A_DIR, ip1->i_labno);
			break;
		}
		if (ip1->i_long != 0) {
			nlf = 0;
			ip2 = ip1->i_fp;
			if (ip2!=NULL && ip2!=&ins && ip2->i_type==LLABEL)
				lab = ip2->i_labno;
			else {
				lab = newlab();
				++nlf;
			}
			genone(revrel(rel), A_LID|A_DIR, lab);
			genone(ZJMP, A_LID|A_DIR, ip1->i_labno);
			if (nlf != 0)
				bput(LLABEL), iput(lab);
			break;
		}
		genone(rel, A_LID|A_DIR, ip1->i_labno);
		break;

	case LINE:
		bput(LINE), iput(ip1->i_line);
		break;

	case CODE:
		if (isvariant(VEMU87)) {
			/*
			 * Under the VEMU87 emulation option, the assembler
			 * precedes 8087 opcodes with emulator calls.
			 */
			i = opinfo[ip1->i_op].op_style;
			if (is8087op(i))
				genone(ZCALL, A_GID|A_DIR, "emu87");
		}
		bput(CODE); bput(ip1->i_op);
		opflag = opinfo[ip1->i_op].op_flag;
		for (i=0; i<ip1->i_naddr; ++i)
			genfield(&ip1->i_af[i], opflag);
		break;
	}
}

static	short	revtab[] = {
	ZJBE,
	ZJB,
	ZJAE,
	ZJA,
	-1,
	ZJNE,
	ZJLE,
	ZJL,
	ZJGE,
	ZJG,
	-1,
	ZJE,
	ZJO,
	ZJS,
	ZJNO,
	ZJPO,
	ZJPE,
	ZJNS
};

revrel(rel)
register rel;
{
	if (rel<ZJA || rel>ZJS || (rel=revtab[rel-ZJA])<0)
		cbotch("bad rev");
	return (rel);
}

This archive runs on limited infrastructure. Preserving old code on modern bandwidth. Automated agents are requested to crawl responsibly.