/* Intel 386 stuff. Copyright (C) 1988, 1989 Free Software Foundation, Inc. This file is part of GDB. This program 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 2 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, write to the Free Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ #include #include "defs.h" #include "param.h" #include "frame.h" #include "inferior.h" #include "gdbcore.h" #ifdef USG #include #endif #include #include #include #include #include #include #include #include #include /* this table must line up with REGISTER_NAMES in m-i386.h */ /* symbols like 'EAX' come from */ 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]); } /* This is broken for cross debugging. Possible solutions are: 1. Don't worry about whether the thing compiles for cross-debugging. Go ahead and call them from i386-tdep.c. 1a. Same thing but use some macros in xm-i386.h so that gdb will compile for cross-debugging but just give an error (or some such behavior) when you attempt to convert floats. 2. Write a portable (in the sense of running on any machine; it would always be for i387 floating-point formats) extended<->double converter (which just deals with the values as arrays of char). 3. Assume the host machine has *some* IEEE chip. However, IEEE does not standardize formats for extended floats (387 is 10 bytes, 68881 is 12 bytes), so this won't work. */ 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 */ 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); }