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Diffstat (limited to 'gdb/m68k-tdep.c')
| -rw-r--r-- | gdb/m68k-tdep.c | 516 |
1 files changed, 516 insertions, 0 deletions
diff --git a/gdb/m68k-tdep.c b/gdb/m68k-tdep.c new file mode 100644 index 0000000..d597efa --- /dev/null +++ b/gdb/m68k-tdep.c @@ -0,0 +1,516 @@ +/* Target dependent code for the Motorola 68000 series. + Copyright (C) 1990, 1992 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ + +#include "defs.h" +#include "frame.h" +#include "symtab.h" +#include "gdbcore.h" +#include "value.h" +#include "gdb_string.h" + + +/* Push an empty stack frame, to record the current PC, etc. */ + +void +m68k_push_dummy_frame () +{ + register CORE_ADDR sp = read_register (SP_REGNUM); + register int regnum; + char raw_buffer[12]; + + sp = push_word (sp, read_register (PC_REGNUM)); + sp = push_word (sp, read_register (FP_REGNUM)); + write_register (FP_REGNUM, sp); + + /* Always save the floating-point registers, whether they exist on + this target or not. */ + for (regnum = FP0_REGNUM + 7; regnum >= FP0_REGNUM; regnum--) + { + read_register_bytes (REGISTER_BYTE (regnum), raw_buffer, 12); + sp = push_bytes (sp, raw_buffer, 12); + } + + for (regnum = FP_REGNUM - 1; regnum >= 0; regnum--) + { + sp = push_word (sp, read_register (regnum)); + } + sp = push_word (sp, read_register (PS_REGNUM)); + write_register (SP_REGNUM, sp); +} + +/* Discard from the stack the innermost frame, + restoring all saved registers. */ + +void +m68k_pop_frame () +{ + register struct frame_info *frame = get_current_frame (); + register CORE_ADDR fp; + register int regnum; + struct frame_saved_regs fsr; + char raw_buffer[12]; + + fp = FRAME_FP (frame); + get_frame_saved_regs (frame, &fsr); + for (regnum = FP0_REGNUM + 7 ; regnum >= FP0_REGNUM ; regnum--) + { + if (fsr.regs[regnum]) + { + read_memory (fsr.regs[regnum], raw_buffer, 12); + write_register_bytes (REGISTER_BYTE (regnum), raw_buffer, 12); + } + } + for (regnum = FP_REGNUM - 1 ; regnum >= 0 ; regnum--) + { + if (fsr.regs[regnum]) + { + write_register (regnum, read_memory_integer (fsr.regs[regnum], 4)); + } + } + if (fsr.regs[PS_REGNUM]) + { + write_register (PS_REGNUM, read_memory_integer (fsr.regs[PS_REGNUM], 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 (); +} + + +/* Given an ip value corresponding to the start of a function, + return the ip of the first instruction after the function + prologue. This is the generic m68k support. Machines which + require something different can override the SKIP_PROLOGUE + macro to point elsewhere. + + Some instructions which typically may appear in a function + prologue include: + + A link instruction, word form: + + link.w %a6,&0 4e56 XXXX + + A link instruction, long form: + + link.l %fp,&F%1 480e XXXX XXXX + + A movm instruction to preserve integer regs: + + movm.l &M%1,(4,%sp) 48ef XXXX XXXX + + A fmovm instruction to preserve float regs: + + fmovm &FPM%1,(FPO%1,%sp) f237 XXXX XXXX XXXX XXXX + + Some profiling setup code (FIXME, not recognized yet): + + lea.l (.L3,%pc),%a1 43fb XXXX XXXX XXXX + bsr _mcount 61ff XXXX XXXX + + */ + +#define P_LINK_L 0x480e +#define P_LINK_W 0x4e56 +#define P_MOV_L 0x207c +#define P_JSR 0x4eb9 +#define P_BSR 0x61ff +#define P_LEA_L 0x43fb +#define P_MOVM_L 0x48ef +#define P_FMOVM 0xf237 +#define P_TRAP 0x4e40 + +CORE_ADDR +m68k_skip_prologue (ip) +CORE_ADDR ip; +{ + register CORE_ADDR limit; + struct symtab_and_line sal; + register int op; + + /* Find out if there is a known limit for the extent of the prologue. + If so, ensure we don't go past it. If not, assume "infinity". */ + + sal = find_pc_line (ip, 0); + limit = (sal.end) ? sal.end : (CORE_ADDR) ~0; + + while (ip < limit) + { + op = read_memory_integer (ip, 2); + op &= 0xFFFF; + + if (op == P_LINK_W) + { + ip += 4; /* Skip link.w */ + } + else if (op == 0x4856) + ip += 2; /* Skip pea %fp */ + else if (op == 0x2c4f) + ip += 2; /* Skip move.l %sp, %fp */ + else if (op == P_LINK_L) + { + ip += 6; /* Skip link.l */ + } + else if (op == P_MOVM_L) + { + ip += 6; /* Skip movm.l */ + } + else if (op == P_FMOVM) + { + ip += 10; /* Skip fmovm */ + } + else + { + break; /* Found unknown code, bail out. */ + } + } + return (ip); +} + +void +m68k_find_saved_regs (frame_info, saved_regs) + struct frame_info *frame_info; + struct frame_saved_regs *saved_regs; +{ + register int regnum; + register int regmask; + register CORE_ADDR next_addr; + register CORE_ADDR pc; + + /* First possible address for a pc in a call dummy for this frame. */ + CORE_ADDR possible_call_dummy_start = + (frame_info)->frame - CALL_DUMMY_LENGTH - FP_REGNUM*4 - 4 - 8*12; + + int nextinsn; + memset (saved_regs, 0, sizeof (*saved_regs)); + if ((frame_info)->pc >= possible_call_dummy_start + && (frame_info)->pc <= (frame_info)->frame) + { + + /* It is a call dummy. We could just stop now, since we know + what the call dummy saves and where. But this code proceeds + to parse the "prologue" which is part of the call dummy. + This is needlessly complex and confusing. FIXME. */ + + next_addr = (frame_info)->frame; + pc = possible_call_dummy_start; + } + else + { + pc = get_pc_function_start ((frame_info)->pc); + + if (0x4856 == read_memory_integer (pc, 2) + && 0x2c4f == read_memory_integer (pc + 2, 2)) + { + /* + pea %fp + move.l %sp, %fp */ + + pc += 4; + next_addr = frame_info->frame; + } + else if (044016 == read_memory_integer (pc, 2)) + /* link.l %fp */ + /* Find the address above the saved + regs using the amount of storage from the link instruction. */ + next_addr = (frame_info)->frame + read_memory_integer (pc += 2, 4), pc+=4; + else if (047126 == read_memory_integer (pc, 2)) + /* link.w %fp */ + /* Find the address above the saved + regs using the amount of storage from the link instruction. */ + next_addr = (frame_info)->frame + read_memory_integer (pc += 2, 2), pc+=2; + else goto lose; + + /* If have an addal #-n, sp next, adjust next_addr. */ + if ((0177777 & read_memory_integer (pc, 2)) == 0157774) + next_addr += read_memory_integer (pc += 2, 4), pc += 4; + } + regmask = read_memory_integer (pc + 2, 2); + + /* Here can come an fmovem. Check for it. */ + nextinsn = 0xffff & read_memory_integer (pc, 2); + if (0xf227 == nextinsn + && (regmask & 0xff00) == 0xe000) + { pc += 4; /* Regmask's low bit is for register fp7, the first pushed */ + for (regnum = FP0_REGNUM + 7; regnum >= FP0_REGNUM; regnum--, regmask >>= 1) + if (regmask & 1) + saved_regs->regs[regnum] = (next_addr -= 12); + regmask = read_memory_integer (pc + 2, 2); } + + /* next should be a moveml to (sp) or -(sp) or a movl r,-(sp) */ + if (0044327 == read_memory_integer (pc, 2)) + { pc += 4; /* Regmask's low bit is for register 0, the first written */ + for (regnum = 0; regnum < 16; regnum++, regmask >>= 1) + if (regmask & 1) + saved_regs->regs[regnum] = (next_addr += 4) - 4; } + else if (0044347 == read_memory_integer (pc, 2)) + { + pc += 4; /* Regmask's low bit is for register 15, the first pushed */ + for (regnum = 15; regnum >= 0; regnum--, regmask >>= 1) + if (regmask & 1) + saved_regs->regs[regnum] = (next_addr -= 4); + } + else if (0x2f00 == (0xfff0 & read_memory_integer (pc, 2))) + { + regnum = 0xf & read_memory_integer (pc, 2); pc += 2; + saved_regs->regs[regnum] = (next_addr -= 4); + /* gcc, at least, may use a pair of movel instructions when saving + exactly 2 registers. */ + if (0x2f00 == (0xfff0 & read_memory_integer (pc, 2))) + { + regnum = 0xf & read_memory_integer (pc, 2); + pc += 2; + saved_regs->regs[regnum] = (next_addr -= 4); + } + } + + /* fmovemx to index of sp may follow. */ + regmask = read_memory_integer (pc + 2, 2); + nextinsn = 0xffff & read_memory_integer (pc, 2); + if (0xf236 == nextinsn + && (regmask & 0xff00) == 0xf000) + { pc += 10; /* Regmask's low bit is for register fp0, the first written */ + for (regnum = FP0_REGNUM + 7; regnum >= FP0_REGNUM; regnum--, regmask >>= 1) + if (regmask & 1) + saved_regs->regs[regnum] = (next_addr += 12) - 12; + regmask = read_memory_integer (pc + 2, 2); } + + /* clrw -(sp); movw ccr,-(sp) may follow. */ + if (0x426742e7 == read_memory_integer (pc, 4)) + saved_regs->regs[PS_REGNUM] = (next_addr -= 4); + lose: ; + saved_regs->regs[SP_REGNUM] = (frame_info)->frame + 8; + saved_regs->regs[FP_REGNUM] = (frame_info)->frame; + saved_regs->regs[PC_REGNUM] = (frame_info)->frame + 4; +#ifdef SIG_SP_FP_OFFSET + /* Adjust saved SP_REGNUM for fake _sigtramp frames. */ + if (frame_info->signal_handler_caller && frame_info->next) + saved_regs->regs[SP_REGNUM] = frame_info->next->frame + SIG_SP_FP_OFFSET; +#endif +} + + +#ifdef USE_PROC_FS /* Target dependent support for /proc */ + +#include <sys/procfs.h> + +/* The /proc interface divides the target machine's register set up into + two different sets, the general register set (gregset) and the floating + point register set (fpregset). For each set, there is an ioctl to get + the current register set and another ioctl to set the current values. + + The actual structure passed through the ioctl interface is, of course, + naturally machine dependent, and is different for each set of registers. + For the m68k for example, the general register set is typically defined + by: + + typedef int gregset_t[18]; + + #define R_D0 0 + ... + #define R_PS 17 + + and the floating point set by: + + typedef struct fpregset { + int f_pcr; + int f_psr; + int f_fpiaddr; + int f_fpregs[8][3]; (8 regs, 96 bits each) + } fpregset_t; + + These routines provide the packing and unpacking of gregset_t and + fpregset_t formatted data. + + */ + +/* Atari SVR4 has R_SR but not R_PS */ + +#if !defined (R_PS) && defined (R_SR) +#define R_PS R_SR +#endif + +/* Given a pointer to a general register set in /proc format (gregset_t *), + unpack the register contents and supply them as gdb's idea of the current + register values. */ + +void +supply_gregset (gregsetp) +gregset_t *gregsetp; +{ + register int regi; + register greg_t *regp = (greg_t *) gregsetp; + + for (regi = 0 ; regi < R_PC ; regi++) + { + supply_register (regi, (char *) (regp + regi)); + } + supply_register (PS_REGNUM, (char *) (regp + R_PS)); + supply_register (PC_REGNUM, (char *) (regp + R_PC)); +} + +void +fill_gregset (gregsetp, regno) +gregset_t *gregsetp; +int regno; +{ + register int regi; + register greg_t *regp = (greg_t *) gregsetp; + extern char registers[]; + + for (regi = 0 ; regi < R_PC ; regi++) + { + if ((regno == -1) || (regno == regi)) + { + *(regp + regi) = *(int *) ®isters[REGISTER_BYTE (regi)]; + } + } + if ((regno == -1) || (regno == PS_REGNUM)) + { + *(regp + R_PS) = *(int *) ®isters[REGISTER_BYTE (PS_REGNUM)]; + } + if ((regno == -1) || (regno == PC_REGNUM)) + { + *(regp + R_PC) = *(int *) ®isters[REGISTER_BYTE (PC_REGNUM)]; + } +} + +#if defined (FP0_REGNUM) + +/* Given a pointer to a floating point register set in /proc format + (fpregset_t *), unpack the register contents and supply them as gdb's + idea of the current floating point register values. */ + +void +supply_fpregset (fpregsetp) +fpregset_t *fpregsetp; +{ + register int regi; + char *from; + + for (regi = FP0_REGNUM ; regi < FPC_REGNUM ; regi++) + { + from = (char *) &(fpregsetp -> f_fpregs[regi-FP0_REGNUM][0]); + supply_register (regi, from); + } + supply_register (FPC_REGNUM, (char *) &(fpregsetp -> f_pcr)); + supply_register (FPS_REGNUM, (char *) &(fpregsetp -> f_psr)); + supply_register (FPI_REGNUM, (char *) &(fpregsetp -> f_fpiaddr)); +} + +/* Given a pointer to a floating point register set in /proc format + (fpregset_t *), update the register specified by REGNO from gdb's idea + of the current floating point register set. If REGNO is -1, update + them all. */ + +void +fill_fpregset (fpregsetp, regno) +fpregset_t *fpregsetp; +int regno; +{ + int regi; + char *to; + char *from; + extern char registers[]; + + for (regi = FP0_REGNUM ; regi < FPC_REGNUM ; regi++) + { + if ((regno == -1) || (regno == regi)) + { + from = (char *) ®isters[REGISTER_BYTE (regi)]; + to = (char *) &(fpregsetp -> f_fpregs[regi-FP0_REGNUM][0]); + memcpy (to, from, REGISTER_RAW_SIZE (regi)); + } + } + if ((regno == -1) || (regno == FPC_REGNUM)) + { + fpregsetp -> f_pcr = *(int *) ®isters[REGISTER_BYTE (FPC_REGNUM)]; + } + if ((regno == -1) || (regno == FPS_REGNUM)) + { + fpregsetp -> f_psr = *(int *) ®isters[REGISTER_BYTE (FPS_REGNUM)]; + } + if ((regno == -1) || (regno == FPI_REGNUM)) + { + fpregsetp -> f_fpiaddr = *(int *) ®isters[REGISTER_BYTE (FPI_REGNUM)]; + } +} + +#endif /* defined (FP0_REGNUM) */ + +#endif /* USE_PROC_FS */ + +#ifdef GET_LONGJMP_TARGET +/* Figure out where the longjmp will land. Slurp the args out of the stack. + We expect the first arg to be a pointer to the jmp_buf structure from which + we extract the pc (JB_PC) that we will land at. The pc is copied into PC. + This routine returns true on success. */ + +int +get_longjmp_target(pc) + CORE_ADDR *pc; +{ + char buf[TARGET_PTR_BIT / TARGET_CHAR_BIT]; + CORE_ADDR sp, jb_addr; + + sp = read_register(SP_REGNUM); + + if (target_read_memory (sp + SP_ARG0, /* Offset of first arg on stack */ + buf, + TARGET_PTR_BIT / TARGET_CHAR_BIT)) + return 0; + + jb_addr = extract_address (buf, TARGET_PTR_BIT / TARGET_CHAR_BIT); + + if (target_read_memory (jb_addr + JB_PC * JB_ELEMENT_SIZE, buf, + TARGET_PTR_BIT / TARGET_CHAR_BIT)) + return 0; + + *pc = extract_address (buf, TARGET_PTR_BIT / TARGET_CHAR_BIT); + + return 1; +} +#endif /* GET_LONGJMP_TARGET */ + +/* Immediately after a function call, return the saved pc before the frame + is setup. For sun3's, we check for the common case of being inside of a + system call, and if so, we know that Sun pushes the call # on the stack + prior to doing the trap. */ + +CORE_ADDR +m68k_saved_pc_after_call(frame) + struct frame_info *frame; +{ +#ifdef SYSCALL_TRAP + int op; + + op = read_memory_integer (frame->pc - SYSCALL_TRAP_OFFSET, 2); + + if (op == SYSCALL_TRAP) + return read_memory_integer (read_register (SP_REGNUM) + 4, 4); + else +#endif /* SYSCALL_TRAP */ + return read_memory_integer (read_register (SP_REGNUM), 4); +} + +void +_initialize_m68k_tdep () +{ + tm_print_insn = print_insn_m68k; +} |