+/* Low level interface to ptrace, for GDB when running on the Intel 386.
+ Copyright (C) 1988, 1989 Free Software Foundation, Inc.
+
+This file is part of GDB.
+
+GDB 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 1, or (at your option)
+any later version.
+
+GDB 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 GDB; see the file COPYING. If not, write to
+the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */
+
+#include <stdio.h>
+#include "defs.h"
+#include "param.h"
+#include "frame.h"
+#include "inferior.h"
+
+#ifdef USG
+#include <sys/types.h>
+#endif
+
+#include <sys/param.h>
+#include <sys/dir.h>
+#include <signal.h>
+#include <sys/user.h>
+#include <sys/ioctl.h>
+#include <fcntl.h>
+
+#ifdef COFF_ENCAPSULATE
+#include "a.out.encap.h"
+#else
+#include <a.out.h>
+#endif
+
+#ifndef N_SET_MAGIC
+#ifdef COFF_FORMAT
+#define N_SET_MAGIC(exec, val) ((exec).magic = (val))
+#else
+#define N_SET_MAGIC(exec, val) ((exec).a_magic = (val))
+#endif
+#endif
+
+#include <sys/file.h>
+#include <sys/stat.h>
+
+#include <sys/reg.h>
+
+extern int errno;
+\f
+/* This function simply calls ptrace with the given arguments.
+ It exists so that all calls to ptrace are isolated in this
+ machine-dependent file. */
+int
+call_ptrace (request, pid, arg3, arg4)
+ int request, pid, arg3, arg4;
+{
+ return ptrace (request, pid, arg3, arg4);
+}
+
+kill_inferior ()
+{
+ if (remote_debugging)
+ return;
+ if (inferior_pid == 0)
+ return;
+ ptrace (8, inferior_pid, 0, 0);
+ wait (0);
+ inferior_died ();
+}
+
+/* This is used when GDB is exiting. It gives less chance of error.*/
+
+kill_inferior_fast ()
+{
+ if (remote_debugging)
+ return;
+ if (inferior_pid == 0)
+ return;
+ ptrace (8, inferior_pid, 0, 0);
+ wait (0);
+}
+
+/* Resume execution of the inferior process.
+ If STEP is nonzero, single-step it.
+ If SIGNAL is nonzero, give it that signal. */
+
+void
+resume (step, signal)
+ int step;
+ int signal;
+{
+ errno = 0;
+ if (remote_debugging)
+ remote_resume (step, signal);
+ else
+ {
+ ptrace (step ? 9 : 7, inferior_pid, 1, signal);
+ if (errno)
+ perror_with_name ("ptrace");
+ }
+}
+\f
+void
+fetch_inferior_registers ()
+{
+ register int regno;
+ register unsigned int regaddr;
+ char buf[MAX_REGISTER_RAW_SIZE];
+ register int i;
+
+ struct user u;
+ unsigned int offset = (char *) &u.u_ar0 - (char *) &u;
+ offset = ptrace (3, inferior_pid, offset, 0) - KERNEL_U_ADDR;
+
+ for (regno = 0; regno < NUM_REGS; regno++)
+ {
+ regaddr = register_addr (regno, offset);
+ for (i = 0; i < REGISTER_RAW_SIZE (regno); i += sizeof (int))
+ {
+ *(int *) &buf[i] = ptrace (3, inferior_pid, regaddr, 0);
+ regaddr += sizeof (int);
+ }
+ supply_register (regno, buf);
+ }
+}
+
+/* Store our register values back into the inferior.
+ If REGNO is -1, do this for all registers.
+ Otherwise, REGNO specifies which register (so we can save time). */
+
+store_inferior_registers (regno)
+ int regno;
+{
+ register unsigned int regaddr;
+ char buf[80];
+
+ struct user u;
+ unsigned int offset = (char *) &u.u_ar0 - (char *) &u;
+ offset = ptrace (3, inferior_pid, offset, 0) - KERNEL_U_ADDR;
+
+ if (regno >= 0)
+ {
+ regaddr = register_addr (regno, offset);
+ errno = 0;
+ ptrace (6, inferior_pid, regaddr, read_register (regno));
+ if (errno != 0)
+ {
+ sprintf (buf, "writing register number %d", regno);
+ perror_with_name (buf);
+ }
+ }
+ else for (regno = 0; regno < NUM_REGS; regno++)
+ {
+ regaddr = register_addr (regno, offset);
+ errno = 0;
+ ptrace (6, inferior_pid, regaddr, read_register (regno));
+ if (errno != 0)
+ {
+ sprintf (buf, "writing register number %d", regno);
+ perror_with_name (buf);
+ }
+ }
+}
+\f
+/* Copy LEN bytes from inferior's memory starting at MEMADDR
+ to debugger memory starting at MYADDR.
+ On failure (cannot read from inferior, usually because address is out
+ of bounds) returns the value of errno. */
+
+int
+read_inferior_memory (memaddr, myaddr, len)
+ CORE_ADDR memaddr;
+ char *myaddr;
+ int len;
+{
+ register int i;
+ /* Round starting address down to longword boundary. */
+ register CORE_ADDR addr = memaddr & - sizeof (int);
+ /* Round ending address up; get number of longwords that makes. */
+ register int count
+ = (((memaddr + len) - addr) + sizeof (int) - 1) / sizeof (int);
+ /* Allocate buffer of that many longwords. */
+ register int *buffer = (int *) alloca (count * sizeof (int));
+ extern int errno;
+
+ /* Read all the longwords */
+ for (i = 0; i < count; i++, addr += sizeof (int))
+ {
+ errno = 0;
+ if (remote_debugging)
+ buffer[i] = remote_fetch_word (addr);
+ else
+ buffer[i] = ptrace (1, inferior_pid, addr, 0);
+ if (errno)
+ return errno;
+ }
+
+ /* Copy appropriate bytes out of the buffer. */
+ bcopy ((char *) buffer + (memaddr & (sizeof (int) - 1)), myaddr, len);
+ return 0;
+}
+
+/* Copy LEN bytes of data from debugger memory at MYADDR
+ to inferior's memory at MEMADDR.
+ On failure (cannot write the inferior)
+ returns the value of errno. */
+
+int
+write_inferior_memory (memaddr, myaddr, len)
+ CORE_ADDR memaddr;
+ char *myaddr;
+ int len;
+{
+ register int i;
+ /* Round starting address down to longword boundary. */
+ register CORE_ADDR addr = memaddr & - sizeof (int);
+ /* Round ending address up; get number of longwords that makes. */
+ register int count
+ = (((memaddr + len) - addr) + sizeof (int) - 1) / sizeof (int);
+ /* Allocate buffer of that many longwords. */
+ register int *buffer = (int *) alloca (count * sizeof (int));
+ extern int errno;
+
+ /* Fill start and end extra bytes of buffer with existing memory data. */
+
+ if (remote_debugging)
+ buffer[0] = remote_fetch_word (addr);
+ else
+ buffer[0] = ptrace (1, inferior_pid, addr, 0);
+
+ if (count > 1)
+ {
+ if (remote_debugging)
+ buffer[count - 1]
+ = remote_fetch_word (addr + (count - 1) * sizeof (int));
+ else
+ buffer[count - 1]
+ = ptrace (1, inferior_pid,
+ addr + (count - 1) * sizeof (int), 0);
+ }
+
+ /* Copy data to be written over corresponding part of buffer */
+
+ bcopy (myaddr, (char *) buffer + (memaddr & (sizeof (int) - 1)), len);
+
+ /* Write the entire buffer. */
+
+ for (i = 0; i < count; i++, addr += sizeof (int))
+ {
+ errno = 0;
+ if (remote_debugging)
+ remote_store_word (addr, buffer[i]);
+ else
+ ptrace (4, inferior_pid, addr, buffer[i]);
+ if (errno)
+ return errno;
+ }
+
+ return 0;
+}
+\f
+/* Work with core dump and executable files, for GDB.
+ This code would be in core.c if it weren't machine-dependent. */
+
+#ifndef N_TXTADDR
+#define N_TXTADDR(hdr) 0
+#endif /* no N_TXTADDR */
+
+#ifndef N_DATADDR
+#define N_DATADDR(hdr) hdr.a_text
+#endif /* no N_DATADDR */
+
+/* Make COFF and non-COFF names for things a little more compatible
+ to reduce conditionals later. */
+
+#ifndef COFF_FORMAT
+#ifndef AOUTHDR
+#define AOUTHDR struct exec
+#endif
+#endif
+
+extern char *sys_siglist[];
+
+
+/* Hook for `exec_file_command' command to call. */
+
+extern void (*exec_file_display_hook) ();
+
+/* File names of core file and executable file. */
+
+extern char *corefile;
+extern char *execfile;
+
+/* Descriptors on which core file and executable file are open.
+ Note that the execchan is closed when an inferior is created
+ and reopened if the inferior dies or is killed. */
+
+extern int corechan;
+extern int execchan;
+
+/* Last modification time of executable file.
+ Also used in source.c to compare against mtime of a source file. */
+
+extern int exec_mtime;
+
+/* Virtual addresses of bounds of the two areas of memory in the core file. */
+
+extern CORE_ADDR data_start;
+extern CORE_ADDR data_end;
+extern CORE_ADDR stack_start;
+extern CORE_ADDR stack_end;
+
+/* Virtual addresses of bounds of two areas of memory in the exec file.
+ Note that the data area in the exec file is used only when there is no core file. */
+
+extern CORE_ADDR text_start;
+extern CORE_ADDR text_end;
+
+extern CORE_ADDR exec_data_start;
+extern CORE_ADDR exec_data_end;
+
+/* Address in executable file of start of text area data. */
+
+extern int text_offset;
+
+/* Address in executable file of start of data area data. */
+
+extern int exec_data_offset;
+
+/* Address in core file of start of data area data. */
+
+extern int data_offset;
+
+/* Address in core file of start of stack area data. */
+
+extern int stack_offset;
+
+#ifdef COFF_FORMAT
+/* various coff data structures */
+
+extern FILHDR file_hdr;
+extern SCNHDR text_hdr;
+extern SCNHDR data_hdr;
+
+#endif /* not COFF_FORMAT */
+
+/* a.out header saved in core file. */
+
+extern AOUTHDR core_aouthdr;
+
+/* a.out header of exec file. */
+
+extern AOUTHDR exec_aouthdr;
+
+extern void validate_files ();
+\f
+core_file_command (filename, from_tty)
+ char *filename;
+ int from_tty;
+{
+ int val;
+ extern char registers[];
+
+ /* Discard all vestiges of any previous core file
+ and mark data and stack spaces as empty. */
+
+ if (corefile)
+ free (corefile);
+ corefile = 0;
+
+ if (corechan >= 0)
+ close (corechan);
+ corechan = -1;
+
+ data_start = 0;
+ data_end = 0;
+ stack_start = STACK_END_ADDR;
+ stack_end = STACK_END_ADDR;
+
+ /* Now, if a new core file was specified, open it and digest it. */
+
+ if (filename)
+ {
+ filename = tilde_expand (filename);
+ make_cleanup (free, filename);
+
+ if (have_inferior_p ())
+ error ("To look at a core file, you must kill the inferior with \"kill\".");
+ corechan = open (filename, O_RDONLY, 0);
+ if (corechan < 0)
+ perror_with_name (filename);
+ /* 4.2-style (and perhaps also sysV-style) core dump file. */
+ {
+ struct user u;
+
+ int reg_offset;
+
+ val = myread (corechan, &u, sizeof u);
+ if (val < 0)
+ perror_with_name (filename);
+ data_start = exec_data_start;
+
+ data_end = data_start + NBPG * u.u_dsize;
+ stack_start = stack_end - NBPG * u.u_ssize;
+ data_offset = NBPG * UPAGES;
+ stack_offset = NBPG * (UPAGES + u.u_dsize);
+ reg_offset = (int) u.u_ar0 - KERNEL_U_ADDR;
+
+ /* I don't know where to find this info.
+ So, for now, mark it as not available. */
+/* N_SET_MAGIC (core_aouthdr, 0); */
+ bzero ((char *) &core_aouthdr, sizeof core_aouthdr);
+
+ /* Read the register values out of the core file and store
+ them where `read_register' will find them. */
+
+ {
+ register int regno;
+
+ for (regno = 0; regno < NUM_REGS; regno++)
+ {
+ char buf[MAX_REGISTER_RAW_SIZE];
+
+ val = lseek (corechan, register_addr (regno, reg_offset), 0);
+ if (val < 0)
+ perror_with_name (filename);
+
+ val = myread (corechan, buf, sizeof buf);
+ if (val < 0)
+ perror_with_name (filename);
+ supply_register (regno, buf);
+ }
+ }
+ }
+ if (filename[0] == '/')
+ corefile = savestring (filename, strlen (filename));
+ else
+ {
+ corefile = concat (current_directory, "/", filename);
+ }
+
+ set_current_frame ( create_new_frame (read_register (FP_REGNUM),
+ read_pc ()));
+ select_frame (get_current_frame (), 0);
+ validate_files ();
+ }
+ else if (from_tty)
+ printf ("No core file now.\n");
+}
+\f
+exec_file_command (filename, from_tty)
+ char *filename;
+ int from_tty;
+{
+ int val;
+
+ /* Eliminate all traces of old exec file.
+ Mark text segment as empty. */
+
+ if (execfile)
+ free (execfile);
+ execfile = 0;
+ data_start = 0;
+ data_end -= exec_data_start;
+ text_start = 0;
+ text_end = 0;
+ exec_data_start = 0;
+ exec_data_end = 0;
+ if (execchan >= 0)
+ close (execchan);
+ execchan = -1;
+
+ /* Now open and digest the file the user requested, if any. */
+
+ if (filename)
+ {
+ filename = tilde_expand (filename);
+ make_cleanup (free, filename);
+
+ execchan = openp (getenv ("PATH"), 1, filename, O_RDONLY, 0,
+ &execfile);
+ if (execchan < 0)
+ perror_with_name (filename);
+
+#ifdef COFF_FORMAT
+ {
+ int aout_hdrsize;
+ int num_sections;
+
+ if (read_file_hdr (execchan, &file_hdr) < 0)
+ error ("\"%s\": not in executable format.", execfile);
+
+ aout_hdrsize = file_hdr.f_opthdr;
+ num_sections = file_hdr.f_nscns;
+
+ if (read_aout_hdr (execchan, &exec_aouthdr, aout_hdrsize) < 0)
+ error ("\"%s\": can't read optional aouthdr", execfile);
+
+ if (read_section_hdr (execchan, _TEXT, &text_hdr, num_sections,
+ aout_hdrsize) < 0)
+ error ("\"%s\": can't read text section header", execfile);
+
+ if (read_section_hdr (execchan, _DATA, &data_hdr, num_sections,
+ aout_hdrsize) < 0)
+ error ("\"%s\": can't read data section header", execfile);
+
+ text_start = exec_aouthdr.text_start;
+ text_end = text_start + exec_aouthdr.tsize;
+ text_offset = text_hdr.s_scnptr;
+ exec_data_start = exec_aouthdr.data_start;
+ exec_data_end = exec_data_start + exec_aouthdr.dsize;
+ exec_data_offset = data_hdr.s_scnptr;
+ data_start = exec_data_start;
+ data_end += exec_data_start;
+ exec_mtime = file_hdr.f_timdat;
+ }
+#else /* not COFF_FORMAT */
+ {
+ struct stat st_exec;
+
+#ifdef HEADER_SEEK_FD
+ HEADER_SEEK_FD (execchan);
+#endif
+
+ val = myread (execchan, &exec_aouthdr, sizeof (AOUTHDR));
+
+ if (val < 0)
+ perror_with_name (filename);
+
+ text_start = N_TXTADDR (exec_aouthdr);
+ exec_data_start = N_DATADDR (exec_aouthdr);
+
+ text_offset = N_TXTOFF (exec_aouthdr);
+ exec_data_offset = N_TXTOFF (exec_aouthdr) + exec_aouthdr.a_text;
+
+ text_end = text_start + exec_aouthdr.a_text;
+ exec_data_end = exec_data_start + exec_aouthdr.a_data;
+ data_start = exec_data_start;
+ data_end += exec_data_start;
+
+ fstat (execchan, &st_exec);
+ exec_mtime = st_exec.st_mtime;
+ }
+#endif /* not COFF_FORMAT */
+
+ validate_files ();
+ }
+ else if (from_tty)
+ printf ("No exec file now.\n");
+
+ /* Tell display code (if any) about the changed file name. */
+ if (exec_file_display_hook)
+ (*exec_file_display_hook) (filename);
+}
+
+/* helper functions for m-i386.h */
+
+/* stdio style buffering to minimize calls to ptrace */
+static CORE_ADDR codestream_next_addr;
+static CORE_ADDR codestream_addr;
+static unsigned char codestream_buf[sizeof (int)];
+static int codestream_off;
+static int codestream_cnt;
+
+#define codestream_tell() (codestream_addr + codestream_off)
+#define codestream_peek() (codestream_cnt == 0 ? \
+ codestream_fill(1): codestream_buf[codestream_off])
+#define codestream_get() (codestream_cnt-- == 0 ? \
+ codestream_fill(0) : codestream_buf[codestream_off++])
+
+static unsigned char
+codestream_fill (peek_flag)
+{
+ codestream_addr = codestream_next_addr;
+ codestream_next_addr += sizeof (int);
+ codestream_off = 0;
+ codestream_cnt = sizeof (int);
+ read_memory (codestream_addr,
+ (unsigned char *)codestream_buf,
+ sizeof (int));
+
+ if (peek_flag)
+ return (codestream_peek());
+ else
+ return (codestream_get());
+}
+
+static void
+codestream_seek (place)
+{
+ codestream_next_addr = place & -sizeof (int);
+ codestream_cnt = 0;
+ codestream_fill (1);
+ while (codestream_tell() != place)
+ codestream_get ();
+}
+
+static void
+codestream_read (buf, count)
+ unsigned char *buf;
+{
+ unsigned char *p;
+ int i;
+ p = buf;
+ for (i = 0; i < count; i++)
+ *p++ = codestream_get ();
+}
+
+/* next instruction is a jump, move to target */
+static
+i386_follow_jump ()
+{
+ int long_delta;
+ short short_delta;
+ char byte_delta;
+ int data16;
+ int pos;
+
+ pos = codestream_tell ();
+
+ data16 = 0;
+ if (codestream_peek () == 0x66)
+ {
+ codestream_get ();
+ data16 = 1;
+ }
+
+ switch (codestream_get ())
+ {
+ case 0xe9:
+ /* relative jump: if data16 == 0, disp32, else disp16 */
+ if (data16)
+ {
+ codestream_read ((unsigned char *)&short_delta, 2);
+ pos += short_delta + 3; /* include size of jmp inst */
+ }
+ else
+ {
+ codestream_read ((unsigned char *)&long_delta, 4);
+ pos += long_delta + 5;
+ }
+ break;
+ case 0xeb:
+ /* relative jump, disp8 (ignore data16) */
+ codestream_read ((unsigned char *)&byte_delta, 1);
+ pos += byte_delta + 2;
+ break;
+ }
+ codestream_seek (pos + data16);
+}
+
+/*
+ * find & return amound a local space allocated, and advance codestream to
+ * first register push (if any)
+ *
+ * if entry sequence doesn't make sense, return -1, and leave
+ * codestream pointer random
+ */
+static long
+i386_get_frame_setup (pc)
+{
+ unsigned char op;
+
+ codestream_seek (pc);
+
+ i386_follow_jump ();
+
+ op = codestream_get ();
+
+ if (op == 0x58) /* popl %eax */
+ {
+ /*
+ * this function must start with
+ *
+ * popl %eax 0x58
+ * xchgl %eax, (%esp) 0x87 0x04 0x24
+ * or xchgl %eax, 0(%esp) 0x87 0x44 0x24 0x00
+ *
+ * (the system 5 compiler puts out the second xchg
+ * inst, and the assembler doesn't try to optimize it,
+ * so the 'sib' form gets generated)
+ *
+ * this sequence is used to get the address of the return
+ * buffer for a function that returns a structure
+ */
+ int pos;
+ unsigned char buf[4];
+ static unsigned char proto1[3] = { 0x87,0x04,0x24 };
+ static unsigned char proto2[4] = { 0x87,0x44,0x24,0x00 };
+ pos = codestream_tell ();
+ codestream_read (buf, 4);
+ if (bcmp (buf, proto1, 3) == 0)
+ pos += 3;
+ else if (bcmp (buf, proto2, 4) == 0)
+ pos += 4;
+
+ codestream_seek (pos);
+ op = codestream_get (); /* update next opcode */
+ }
+
+ if (op == 0x55) /* pushl %esp */
+ {
+ /* check for movl %esp, %ebp - can be written two ways */
+ switch (codestream_get ())
+ {
+ case 0x8b:
+ if (codestream_get () != 0xec)
+ return (-1);
+ break;
+ case 0x89:
+ if (codestream_get () != 0xe5)
+ return (-1);
+ break;
+ default:
+ return (-1);
+ }
+ /* check for stack adjustment
+ *
+ * subl $XXX, %esp
+ *
+ * note: you can't subtract a 16 bit immediate
+ * from a 32 bit reg, so we don't have to worry
+ * about a data16 prefix
+ */
+ op = codestream_peek ();
+ if (op == 0x83)
+ {
+ /* subl with 8 bit immed */
+ codestream_get ();
+ if (codestream_get () != 0xec)
+ return (-1);
+ /* subl with signed byte immediate
+ * (though it wouldn't make sense to be negative)
+ */
+ return (codestream_get());
+ }
+ else if (op == 0x81)
+ {
+ /* subl with 32 bit immed */
+ int locals;
+ codestream_get();
+ if (codestream_get () != 0xec)
+ return (-1);
+ /* subl with 32 bit immediate */
+ codestream_read ((unsigned char *)&locals, 4);
+ return (locals);
+ }
+ else
+ {
+ return (0);
+ }
+ }
+ else if (op == 0xc8)
+ {
+ /* enter instruction: arg is 16 bit unsigned immed */
+ unsigned short slocals;
+ codestream_read ((unsigned char *)&slocals, 2);
+ codestream_get (); /* flush final byte of enter instruction */
+ return (slocals);
+ }
+ return (-1);
+}
+
+/* Return number of args passed to a frame.
+ Can return -1, meaning no way to tell. */
+
+/* on the 386, the instruction following the call could be:
+ * popl %ecx - one arg
+ * addl $imm, %esp - imm/4 args; imm may be 8 or 32 bits
+ * anything else - zero args
+ */
+
+int
+i386_frame_num_args (fi)
+ struct frame_info fi;
+{
+ int retpc;
+ unsigned char op;
+ struct frame_info *pfi;
+
+ pfi = get_prev_frame_info ((fi));
+ if (pfi == 0)
+ {
+ /* Note: this can happen if we are looking at the frame for
+ main, because FRAME_CHAIN_VALID won't let us go into
+ start. If we have debugging symbols, that's not really
+ a big deal; it just means it will only show as many arguments
+ to main as are declared. */
+ return -1;
+ }
+ else
+ {
+ retpc = pfi->pc;
+ op = read_memory_integer (retpc, 1);
+ if (op == 0x59)
+ /* pop %ecx */
+ return 1;
+ else if (op == 0x83)
+ {
+ op = read_memory_integer (retpc+1, 1);
+ if (op == 0xc4)
+ /* addl $<signed imm 8 bits>, %esp */
+ return (read_memory_integer (retpc+2,1)&0xff)/4;
+ else
+ return 0;
+ }
+ else if (op == 0x81)
+ { /* add with 32 bit immediate */
+ op = read_memory_integer (retpc+1, 1);
+ if (op == 0xc4)
+ /* addl $<imm 32>, %esp */
+ return read_memory_integer (retpc+2, 4) / 4;
+ else
+ return 0;
+ }
+ else
+ {
+ return 0;
+ }
+ }
+}
+
+/*
+ * parse the first few instructions of the function to see
+ * what registers were stored.
+ *
+ * We handle these cases:
+ *
+ * The startup sequence can be at the start of the function,
+ * or the function can start with a branch to startup code at the end.
+ *
+ * %ebp can be set up with either the 'enter' instruction, or
+ * 'pushl %ebp, movl %esp, %ebp' (enter is too slow to be useful,
+ * but was once used in the sys5 compiler)
+ *
+ * Local space is allocated just below the saved %ebp by either the
+ * 'enter' instruction, or by 'subl $<size>, %esp'. 'enter' has
+ * a 16 bit unsigned argument for space to allocate, and the
+ * 'addl' instruction could have either a signed byte, or
+ * 32 bit immediate.
+ *
+ * Next, the registers used by this function are pushed. In
+ * the sys5 compiler they will always be in the order: %edi, %esi, %ebx
+ * (and sometimes a harmless bug causes it to also save but not restore %eax);
+ * however, the code below is willing to see the pushes in any order,
+ * and will handle up to 8 of them.
+ *
+ * If the setup sequence is at the end of the function, then the
+ * next instruction will be a branch back to the start.
+ */
+
+i386_frame_find_saved_regs (fip, fsrp)
+ struct frame_info *fip;
+ struct frame_saved_regs *fsrp;
+{
+ unsigned long locals;
+ unsigned char *p;
+ unsigned char op;
+ CORE_ADDR dummy_bottom;
+ CORE_ADDR adr;
+ int i;
+
+ bzero (fsrp, sizeof *fsrp);
+
+ /* if frame is the end of a dummy, compute where the
+ * beginning would be
+ */
+ dummy_bottom = fip->frame - 4 - NUM_REGS*4 - CALL_DUMMY_LENGTH;
+
+ /* check if the PC is in the stack, in a dummy frame */
+ if (dummy_bottom <= fip->pc && fip->pc <= fip->frame)
+ {
+ /* all regs were saved by push_call_dummy () */
+ adr = fip->frame - 4;
+ for (i = 0; i < NUM_REGS; i++)
+ {
+ fsrp->regs[i] = adr;
+ adr -= 4;
+ }
+ return;
+ }
+
+ locals = i386_get_frame_setup (get_pc_function_start (fip->pc));
+
+ if (locals >= 0)
+ {
+ adr = fip->frame - 4 - locals;
+ for (i = 0; i < 8; i++)
+ {
+ op = codestream_get ();
+ if (op < 0x50 || op > 0x57)
+ break;
+ fsrp->regs[op - 0x50] = adr;
+ adr -= 4;
+ }
+ }
+
+ fsrp->regs[PC_REGNUM] = fip->frame + 4;
+ fsrp->regs[FP_REGNUM] = fip->frame;
+}
+
+/* return pc of first real instruction */
+i386_skip_prologue (pc)
+{
+ unsigned char op;
+ int i;
+
+ if (i386_get_frame_setup (pc) < 0)
+ return (pc);
+
+ /* found valid frame setup - codestream now points to
+ * start of push instructions for saving registers
+ */
+
+ /* skip over register saves */
+ for (i = 0; i < 8; i++)
+ {
+ op = codestream_peek ();
+ /* break if not pushl inst */
+ if (op < 0x50 || op > 0x57)
+ break;
+ codestream_get ();
+ }
+
+ i386_follow_jump ();
+
+ return (codestream_tell ());
+}
+
+i386_push_dummy_frame ()
+{
+ CORE_ADDR sp = read_register (SP_REGNUM);
+ int regnum;
+
+ sp = push_word (sp, read_register (PC_REGNUM));
+ sp = push_word (sp, read_register (FP_REGNUM));
+ write_register (FP_REGNUM, sp);
+ for (regnum = 0; regnum < NUM_REGS; regnum++)
+ sp = push_word (sp, read_register (regnum));
+ write_register (SP_REGNUM, sp);
+}
+
+i386_pop_frame ()
+{
+ FRAME frame = get_current_frame ();
+ CORE_ADDR fp;
+ int regnum;
+ struct frame_saved_regs fsr;
+ struct frame_info *fi;
+
+ fi = get_frame_info (frame);
+ fp = fi->frame;
+ get_frame_saved_regs (fi, &fsr);
+ for (regnum = 0; regnum < NUM_REGS; regnum++)
+ {
+ CORE_ADDR adr;
+ adr = fsr.regs[regnum];
+ if (adr)
+ write_register (regnum, read_memory_integer (adr, 4));
+ }
+ write_register (FP_REGNUM, read_memory_integer (fp, 4));
+ write_register (PC_REGNUM, read_memory_integer (fp + 4, 4));
+ write_register (SP_REGNUM, fp + 8);
+ flush_cached_frames ();
+ set_current_frame ( create_new_frame (read_register (FP_REGNUM),
+ read_pc ()));
+}
+
+/* this table must line up with REGISTER_NAMES in m-i386.h */
+/* symbols like 'EAX' come from <sys/reg.h> */
+static int regmap[] =
+{
+ EAX, ECX, EDX, EBX,
+ UESP, EBP, ESI, EDI,
+ EIP, EFL, CS, SS,
+ DS, ES, FS, GS,
+};
+
+/* blockend is the value of u.u_ar0, and points to the
+ * place where GS is stored
+ */
+i386_register_u_addr (blockend, regnum)
+{
+#if 0
+ /* this will be needed if fp registers are reinstated */
+ /* for now, you can look at them with 'info float'
+ * sys5 wont let you change them with ptrace anyway
+ */
+ if (regnum >= FP0_REGNUM && regnum <= FP7_REGNUM)
+ {
+ int ubase, fpstate;
+ struct user u;
+ ubase = blockend + 4 * (SS + 1) - KSTKSZ;
+ fpstate = ubase + ((char *)&u.u_fpstate - (char *)&u);
+ return (fpstate + 0x1c + 10 * (regnum - FP0_REGNUM));
+ }
+ else
+#endif
+ return (blockend + 4 * regmap[regnum]);
+
+}
+
+i387_to_double (from, to)
+ char *from;
+ char *to;
+{
+ long *lp;
+ /* push extended mode on 387 stack, then pop in double mode
+ *
+ * first, set exception masks so no error is generated -
+ * number will be rounded to inf or 0, if necessary
+ */
+ asm ("pushl %eax"); /* grab a stack slot */
+ asm ("fstcw (%esp)"); /* get 387 control word */
+ asm ("movl (%esp),%eax"); /* save old value */
+ asm ("orl $0x3f,%eax"); /* mask all exceptions */
+ asm ("pushl %eax");
+ asm ("fldcw (%esp)"); /* load new value into 387 */
+
+ asm ("movl 8(%ebp),%eax");
+ asm ("fldt (%eax)"); /* push extended number on 387 stack */
+ asm ("fwait");
+ asm ("movl 12(%ebp),%eax");
+ asm ("fstpl (%eax)"); /* pop double */
+ asm ("fwait");
+
+ asm ("popl %eax"); /* flush modified control word */
+ asm ("fnclex"); /* clear exceptions */
+ asm ("fldcw (%esp)"); /* restore original control word */
+ asm ("popl %eax"); /* flush saved copy */
+}
+
+double_to_i387 (from, to)
+ char *from;
+ char *to;
+{
+ /* push double mode on 387 stack, then pop in extended mode
+ * no errors are possible because every 64-bit pattern
+ * can be converted to an extended
+ */
+ asm ("movl 8(%ebp),%eax");
+ asm ("fldl (%eax)");
+ asm ("fwait");
+ asm ("movl 12(%ebp),%eax");
+ asm ("fstpt (%eax)");
+ asm ("fwait");
+}
+
+struct env387
+{
+ unsigned short control;
+ unsigned short r0;
+ unsigned short status;
+ unsigned short r1;
+ unsigned short tag;
+ unsigned short r2;
+ unsigned long eip;
+ unsigned short code_seg;
+ unsigned short opcode;
+ unsigned long operand;
+ unsigned short operand_seg;
+ unsigned short r3;
+ unsigned char regs[8][10];
+};
+
+static
+print_387_control_word (control)
+unsigned short control;
+{
+ printf ("control 0x%04x: ", control);
+ printf ("compute to ");
+ switch ((control >> 8) & 3)
+ {
+ case 0: printf ("24 bits; "); break;
+ case 1: printf ("(bad); "); break;
+ case 2: printf ("53 bits; "); break;
+ case 3: printf ("64 bits; "); break;
+ }
+ printf ("round ");
+ switch ((control >> 10) & 3)
+ {
+ case 0: printf ("NEAREST; "); break;
+ case 1: printf ("DOWN; "); break;
+ case 2: printf ("UP; "); break;
+ case 3: printf ("CHOP; "); break;
+ }
+ if (control & 0x3f)
+ {
+ printf ("mask:");
+ if (control & 0x0001) printf (" INVALID");
+ if (control & 0x0002) printf (" DENORM");
+ if (control & 0x0004) printf (" DIVZ");
+ if (control & 0x0008) printf (" OVERF");
+ if (control & 0x0010) printf (" UNDERF");
+ if (control & 0x0020) printf (" LOS");
+ printf (";");
+ }
+ printf ("\n");
+ if (control & 0xe080) printf ("warning: reserved bits on 0x%x\n",
+ control & 0xe080);
+}
+
+static
+print_387_status_word (status)
+ unsigned short status;
+{
+ printf ("status 0x%04x: ", status);
+ if (status & 0xff)
+ {
+ printf ("exceptions:");
+ if (status & 0x0001) printf (" INVALID");
+ if (status & 0x0002) printf (" DENORM");
+ if (status & 0x0004) printf (" DIVZ");
+ if (status & 0x0008) printf (" OVERF");
+ if (status & 0x0010) printf (" UNDERF");
+ if (status & 0x0020) printf (" LOS");
+ if (status & 0x0040) printf (" FPSTACK");
+ printf ("; ");
+ }
+ printf ("flags: %d%d%d%d; ",
+ (status & 0x4000) != 0,
+ (status & 0x0400) != 0,
+ (status & 0x0200) != 0,
+ (status & 0x0100) != 0);
+
+ printf ("top %d\n", (status >> 11) & 7);
+}
+
+static
+print_387_status (status, ep)
+ unsigned short status;
+ struct env387 *ep;
+{
+ int i;
+ int bothstatus;
+ int top;
+ int fpreg;
+ unsigned char *p;
+
+ bothstatus = ((status != 0) && (ep->status != 0));
+ if (status != 0)
+ {
+ if (bothstatus)
+ printf ("u: ");
+ print_387_status_word (status);
+ }
+
+ if (ep->status != 0)
+ {
+ if (bothstatus)
+ printf ("e: ");
+ print_387_status_word (ep->status);
+ }
+
+ print_387_control_word (ep->control);
+ printf ("last exception: ");
+ printf ("opcode 0x%x; ", ep->opcode);
+ printf ("pc 0x%x:0x%x; ", ep->code_seg, ep->eip);
+ printf ("operand 0x%x:0x%x\n", ep->operand_seg, ep->operand);
+
+ top = (ep->status >> 11) & 7;
+
+ printf ("regno tag msb lsb value\n");
+ for (fpreg = 7; fpreg >= 0; fpreg--)
+ {
+ double val;
+
+ printf ("%s %d: ", fpreg == top ? "=>" : " ", fpreg);
+
+ switch ((ep->tag >> (fpreg * 2)) & 3)
+ {
+ case 0: printf ("valid "); break;
+ case 1: printf ("zero "); break;
+ case 2: printf ("trap "); break;
+ case 3: printf ("empty "); break;
+ }
+ for (i = 9; i >= 0; i--)
+ printf ("%02x", ep->regs[fpreg][i]);
+
+ i387_to_double (ep->regs[fpreg], (char *)&val);
+ printf (" %g\n", val);
+ }
+ if (ep->r0)
+ printf ("warning: reserved0 is 0x%x\n", ep->r0);
+ if (ep->r1)
+ printf ("warning: reserved1 is 0x%x\n", ep->r1);
+ if (ep->r2)
+ printf ("warning: reserved2 is 0x%x\n", ep->r2);
+ if (ep->r3)
+ printf ("warning: reserved3 is 0x%x\n", ep->r3);
+}
+
+#ifndef U_FPSTATE
+#define U_FPSTATE(u) u.u_fpstate
+#endif
+
+i386_float_info ()
+{
+ struct user u; /* just for address computations */
+ int i;
+ /* fpstate defined in <sys/user.h> */
+ struct fpstate *fpstatep;
+ char buf[sizeof (struct fpstate) + 2 * sizeof (int)];
+ unsigned int uaddr;
+ char fpvalid;
+ unsigned int rounded_addr;
+ unsigned int rounded_size;
+ extern int corechan;
+ int skip;
+
+ uaddr = (char *)&u.u_fpvalid - (char *)&u;
+ if (have_inferior_p())
+ {
+ unsigned int data;
+ unsigned int mask;
+
+ rounded_addr = uaddr & -sizeof (int);
+ data = ptrace (3, inferior_pid, rounded_addr, 0);
+ mask = 0xff << ((uaddr - rounded_addr) * 8);
+
+ fpvalid = ((data & mask) != 0);
+ }
+ else
+ {
+ if (lseek (corechan, uaddr, 0) < 0)
+ perror ("seek on core file");
+ if (myread (corechan, &fpvalid, 1) < 0)
+ perror ("read on core file");
+
+ }
+
+ if (fpvalid == 0)
+ {
+ printf ("no floating point status saved\n");
+ return;
+ }
+
+ uaddr = (char *)&U_FPSTATE(u) - (char *)&u;
+ if (have_inferior_p ())
+ {
+ int *ip;
+
+ rounded_addr = uaddr & -sizeof (int);
+ rounded_size = (((uaddr + sizeof (struct fpstate)) - uaddr) +
+ sizeof (int) - 1) / sizeof (int);
+ skip = uaddr - rounded_addr;
+
+ ip = (int *)buf;
+ for (i = 0; i < rounded_size; i++)
+ {
+ *ip++ = ptrace (3, inferior_pid, rounded_addr, 0);
+ rounded_addr += sizeof (int);
+ }
+ }
+ else
+ {
+ if (lseek (corechan, uaddr, 0) < 0)
+ perror_with_name ("seek on core file");
+ if (myread (corechan, buf, sizeof (struct fpstate)) < 0)
+ perror_with_name ("read from core file");
+ skip = 0;
+ }
+
+ fpstatep = (struct fpstate *)(buf + skip);
+ print_387_status (fpstatep->status, (struct env387 *)fpstatep->state);
+}
+
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