fis-gtm/sr_i386/find_line_call.c

/****************************************************************
 *								*
 *	Copyright 2001, 2012 Fidelity Information Services, Inc	*
 *								*
 *	This source code contains the intellectual property	*
 *	of its copyright holder(s), and is made available	*
 *	under a license.  If you do not know the terms of	*
 *	the license, please stop and do not read further.	*
 *								*
 ****************************************************************/

#include "mdef.h"
#include "xfer_enum.h"
#include "i386.h"
#include "rtnhdr.h"	/* Needed by zbreak.h */
#include "zbreak.h"

zb_code  *find_line_call(void *addr)
{
	unsigned char *call_addr;
	union
	{
		ModR_M		modrm;
		unsigned char	byte;
	} modrm_byte;

	call_addr = (unsigned char *)addr;
	modrm_byte.byte = *(call_addr + 1);
	if ((I386_INS_Grp5_Prefix == *call_addr) && (I386_INS_CALL_Ev == modrm_byte.modrm.reg_opcode))
	{
		call_addr++;
		assert(I386_REG_EBX == modrm_byte.modrm.r_m);
		call_addr++;
		if (I386_MOD32_BASE_DISP_8 == modrm_byte.modrm.mod)
		{
			if ((xf_linestart * SIZEOF(int4) == *call_addr) ||
			    (xf_zbstart * SIZEOF(int4) == *call_addr))
				return (zb_code *)call_addr;
			call_addr++;
		} else
		{
			assert (I386_MOD32_BASE_DISP_32 == modrm_byte.modrm.mod);
			return (zb_code *)addr;
		}
	}

	modrm_byte.byte = *(call_addr + 1);
	if ((I386_INS_PUSH_Ib == *call_addr) || (I386_INS_PUSH_Iv == *call_addr))
	{
		while ((I386_INS_PUSH_Ib == *call_addr) || (I386_INS_PUSH_Iv == *call_addr))
		{
			if (I386_INS_PUSH_Ib == *call_addr)
				call_addr += 1 + SIZEOF(unsigned char);
			else
			{
				assert(I386_INS_PUSH_Iv == *call_addr);
				call_addr += 1 + SIZEOF(int4);
			}
		}
		modrm_byte.byte = *(call_addr + 1);
		if ((I386_INS_Grp5_Prefix != *call_addr++) || (I386_INS_CALL_Ev != modrm_byte.modrm.reg_opcode))
			return (zb_code *)addr;
		assert((I386_MOD32_BASE_DISP_8 == modrm_byte.modrm.mod) || (I386_MOD32_BASE_DISP_32 == modrm_byte.modrm.mod));
		assert(I386_REG_EBX == modrm_byte.modrm.r_m);
		call_addr++;
		if (I386_MOD32_BASE_DISP_8 == modrm_byte.modrm.mod)
		{
			if ((xf_linefetch * SIZEOF(int4) != *call_addr) && (xf_zbfetch * SIZEOF(int4) != *call_addr))
				return (zb_code *)addr;
		}
	}
	else if ((I386_INS_Grp5_Prefix == *call_addr) && (I386_INS_CALL_Ev != modrm_byte.modrm.reg_opcode))
	{
		call_addr++;
		assert((I386_MOD32_BASE_DISP_8 == modrm_byte.modrm.mod) || (I386_MOD32_BASE_DISP_32 == modrm_byte.modrm.mod));
		assert(I386_REG_EBX == modrm_byte.modrm.r_m);
		call_addr++;
		if (I386_MOD32_BASE_DISP_8 == modrm_byte.modrm.mod)
		{
			if ((xf_linestart * SIZEOF(int4) != *call_addr) && (xf_zbstart * SIZEOF(int4) != *call_addr))
				return (zb_code *)addr;
		}
	}
	return (zb_code *)call_addr;
}