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Diffstat (limited to 'gdb/mn10300-tdep.c')
| -rw-r--r-- | gdb/mn10300-tdep.c | 791 |
1 files changed, 791 insertions, 0 deletions
diff --git a/gdb/mn10300-tdep.c b/gdb/mn10300-tdep.c new file mode 100644 index 0000000..6c43176 --- /dev/null +++ b/gdb/mn10300-tdep.c @@ -0,0 +1,791 @@ +/* Target-dependent code for the Matsushita MN10300 for GDB, the GNU debugger. + Copyright 1996, 1997, 1998 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 "inferior.h" +#include "obstack.h" +#include "target.h" +#include "value.h" +#include "bfd.h" +#include "gdb_string.h" +#include "gdbcore.h" +#include "symfile.h" + +static char *mn10300_generic_register_names[] = +{ "d0", "d1", "d2", "d3", "a0", "a1", "a2", "a3", + "sp", "pc", "mdr", "psw", "lir", "lar", "", "", + "", "", "", "", "", "", "", "", + "", "", "", "", "", "", "", "fp" }; + +char **mn10300_register_names = mn10300_generic_register_names; + +static CORE_ADDR mn10300_analyze_prologue PARAMS ((struct frame_info *fi, + CORE_ADDR pc)); + +/* Additional info used by the frame */ + +struct frame_extra_info +{ + int status; + int stack_size; +}; + +static struct frame_info *analyze_dummy_frame PARAMS ((CORE_ADDR, CORE_ADDR)); +static struct frame_info * +analyze_dummy_frame (pc, frame) + CORE_ADDR pc; + CORE_ADDR frame; +{ + static struct frame_info *dummy = NULL; + if (dummy == NULL) + { + dummy = xmalloc (sizeof (struct frame_info)); + dummy->saved_regs = xmalloc (SIZEOF_FRAME_SAVED_REGS); + dummy->extra_info = xmalloc (sizeof (struct frame_extra_info)); + } + dummy->next = NULL; + dummy->prev = NULL; + dummy->pc = pc; + dummy->frame = frame; + dummy->extra_info->status = 0; + dummy->extra_info->stack_size = 0; + memset (dummy->saved_regs, '\000', SIZEOF_FRAME_SAVED_REGS); + mn10300_analyze_prologue (dummy, 0); + return dummy; +} + +/* Values for frame_info.status */ + +#define MY_FRAME_IN_SP 0x1 +#define MY_FRAME_IN_FP 0x2 +#define NO_MORE_FRAMES 0x4 + + +/* Should call_function allocate stack space for a struct return? */ +int +mn10300_use_struct_convention (gcc_p, type) + int gcc_p; + struct type *type; +{ + return (TYPE_NFIELDS (type) > 1 || TYPE_LENGTH (type) > 8); +} + +/* The breakpoint instruction must be the same size as the smallest + instruction in the instruction set. + + The Matsushita mn10x00 processors have single byte instructions + so we need a single byte breakpoint. Matsushita hasn't defined + one, so we defined it ourselves. */ + +unsigned char * +mn10300_breakpoint_from_pc (bp_addr, bp_size) + CORE_ADDR *bp_addr; + int *bp_size; +{ + static char breakpoint[] = {0xff}; + *bp_size = 1; + return breakpoint; +} + + +/* Fix fi->frame if it's bogus at this point. This is a helper + function for mn10300_analyze_prologue. */ + +static void +fix_frame_pointer (fi, stack_size) + struct frame_info *fi; + int stack_size; +{ + if (fi && fi->next == NULL) + { + if (fi->extra_info->status & MY_FRAME_IN_SP) + fi->frame = read_sp () - stack_size; + else if (fi->extra_info->status & MY_FRAME_IN_FP) + fi->frame = read_register (A3_REGNUM); + } +} + + +/* Set offsets of registers saved by movm instruction. + This is a helper function for mn10300_analyze_prologue. */ + +static void +set_movm_offsets (fi, movm_args) + struct frame_info *fi; + int movm_args; +{ + int offset = 0; + + if (fi == NULL || movm_args == 0) + return; + + if (movm_args & 0x10) + { + fi->saved_regs[A3_REGNUM] = fi->frame + offset; + offset += 4; + } + if (movm_args & 0x20) + { + fi->saved_regs[A2_REGNUM] = fi->frame + offset; + offset += 4; + } + if (movm_args & 0x40) + { + fi->saved_regs[D3_REGNUM] = fi->frame + offset; + offset += 4; + } + if (movm_args & 0x80) + { + fi->saved_regs[D2_REGNUM] = fi->frame + offset; + offset += 4; + } +} + + +/* The main purpose of this file is dealing with prologues to extract + information about stack frames and saved registers. + + For reference here's how prologues look on the mn10300: + + With frame pointer: + movm [d2,d3,a2,a3],sp + mov sp,a3 + add <size>,sp + + Without frame pointer: + movm [d2,d3,a2,a3],sp (if needed) + add <size>,sp + + One day we might keep the stack pointer constant, that won't + change the code for prologues, but it will make the frame + pointerless case much more common. */ + +/* Analyze the prologue to determine where registers are saved, + the end of the prologue, etc etc. Return the end of the prologue + scanned. + + We store into FI (if non-null) several tidbits of information: + + * stack_size -- size of this stack frame. Note that if we stop in + certain parts of the prologue/epilogue we may claim the size of the + current frame is zero. This happens when the current frame has + not been allocated yet or has already been deallocated. + + * fsr -- Addresses of registers saved in the stack by this frame. + + * status -- A (relatively) generic status indicator. It's a bitmask + with the following bits: + + MY_FRAME_IN_SP: The base of the current frame is actually in + the stack pointer. This can happen for frame pointerless + functions, or cases where we're stopped in the prologue/epilogue + itself. For these cases mn10300_analyze_prologue will need up + update fi->frame before returning or analyzing the register + save instructions. + + MY_FRAME_IN_FP: The base of the current frame is in the + frame pointer register ($a2). + + NO_MORE_FRAMES: Set this if the current frame is "start" or + if the first instruction looks like mov <imm>,sp. This tells + frame chain to not bother trying to unwind past this frame. */ + +static CORE_ADDR +mn10300_analyze_prologue (fi, pc) + struct frame_info *fi; + CORE_ADDR pc; +{ + CORE_ADDR func_addr, func_end, addr, stop; + CORE_ADDR stack_size; + int imm_size; + unsigned char buf[4]; + int status, movm_args = 0; + char *name; + + /* Use the PC in the frame if it's provided to look up the + start of this function. */ + pc = (fi ? fi->pc : pc); + + /* Find the start of this function. */ + status = find_pc_partial_function (pc, &name, &func_addr, &func_end); + + /* Do nothing if we couldn't find the start of this function or if we're + stopped at the first instruction in the prologue. */ + if (status == 0) + return pc; + + /* If we're in start, then give up. */ + if (strcmp (name, "start") == 0) + { + if (fi != NULL) + fi->extra_info->status = NO_MORE_FRAMES; + return pc; + } + + /* At the start of a function our frame is in the stack pointer. */ + if (fi) + fi->extra_info->status = MY_FRAME_IN_SP; + + /* Get the next two bytes into buf, we need two because rets is a two + byte insn and the first isn't enough to uniquely identify it. */ + status = read_memory_nobpt (pc, buf, 2); + if (status != 0) + return pc; + + /* If we're physically on an "rets" instruction, then our frame has + already been deallocated. Note this can also be true for retf + and ret if they specify a size of zero. + + In this case fi->frame is bogus, we need to fix it. */ + if (fi && buf[0] == 0xf0 && buf[1] == 0xfc) + { + if (fi->next == NULL) + fi->frame = read_sp (); + return fi->pc; + } + + /* Similarly if we're stopped on the first insn of a prologue as our + frame hasn't been allocated yet. */ + if (fi && fi->pc == func_addr) + { + if (fi->next == NULL) + fi->frame = read_sp (); + return fi->pc; + } + + /* Figure out where to stop scanning. */ + stop = fi ? fi->pc : func_end; + + /* Don't walk off the end of the function. */ + stop = stop > func_end ? func_end : stop; + + /* Start scanning on the first instruction of this function. */ + addr = func_addr; + + /* Suck in two bytes. */ + status = read_memory_nobpt (addr, buf, 2); + if (status != 0) + { + fix_frame_pointer (fi, 0); + return addr; + } + + /* First see if this insn sets the stack pointer; if so, it's something + we won't understand, so quit now. */ + if (buf[0] == 0xf2 && (buf[1] & 0xf3) == 0xf0) + { + if (fi) + fi->extra_info->status = NO_MORE_FRAMES; + return addr; + } + + /* Now look for movm [regs],sp, which saves the callee saved registers. + + At this time we don't know if fi->frame is valid, so we only note + that we encountered a movm instruction. Later, we'll set the entries + in fsr.regs as needed. */ + if (buf[0] == 0xcf) + { + /* Extract the register list for the movm instruction. */ + status = read_memory_nobpt (addr + 1, buf, 1); + movm_args = *buf; + + addr += 2; + + /* Quit now if we're beyond the stop point. */ + if (addr >= stop) + { + /* Fix fi->frame since it's bogus at this point. */ + if (fi && fi->next == NULL) + fi->frame = read_sp (); + + /* Note if/where callee saved registers were saved. */ + set_movm_offsets (fi, movm_args); + return addr; + } + + /* Get the next two bytes so the prologue scan can continue. */ + status = read_memory_nobpt (addr, buf, 2); + if (status != 0) + { + /* Fix fi->frame since it's bogus at this point. */ + if (fi && fi->next == NULL) + fi->frame = read_sp (); + + /* Note if/where callee saved registers were saved. */ + set_movm_offsets (fi, movm_args); + return addr; + } + } + + /* Now see if we set up a frame pointer via "mov sp,a3" */ + if (buf[0] == 0x3f) + { + addr += 1; + + /* The frame pointer is now valid. */ + if (fi) + { + fi->extra_info->status |= MY_FRAME_IN_FP; + fi->extra_info->status &= ~MY_FRAME_IN_SP; + } + + /* Quit now if we're beyond the stop point. */ + if (addr >= stop) + { + /* Fix fi->frame if it's bogus at this point. */ + fix_frame_pointer (fi, 0); + + /* Note if/where callee saved registers were saved. */ + set_movm_offsets (fi, movm_args); + return addr; + } + + /* Get two more bytes so scanning can continue. */ + status = read_memory_nobpt (addr, buf, 2); + if (status != 0) + { + /* Fix fi->frame if it's bogus at this point. */ + fix_frame_pointer (fi, 0); + + /* Note if/where callee saved registers were saved. */ + set_movm_offsets (fi, movm_args); + return addr; + } + } + + /* Next we should allocate the local frame. No more prologue insns + are found after allocating the local frame. + + Search for add imm8,sp (0xf8feXX) + or add imm16,sp (0xfafeXXXX) + or add imm32,sp (0xfcfeXXXXXXXX). + + If none of the above was found, then this prologue has no + additional stack. */ + + status = read_memory_nobpt (addr, buf, 2); + if (status != 0) + { + /* Fix fi->frame if it's bogus at this point. */ + fix_frame_pointer (fi, 0); + + /* Note if/where callee saved registers were saved. */ + set_movm_offsets (fi, movm_args); + return addr; + } + + imm_size = 0; + if (buf[0] == 0xf8 && buf[1] == 0xfe) + imm_size = 1; + else if (buf[0] == 0xfa && buf[1] == 0xfe) + imm_size = 2; + else if (buf[0] == 0xfc && buf[1] == 0xfe) + imm_size = 4; + + if (imm_size != 0) + { + /* Suck in imm_size more bytes, they'll hold the size of the + current frame. */ + status = read_memory_nobpt (addr + 2, buf, imm_size); + if (status != 0) + { + /* Fix fi->frame if it's bogus at this point. */ + fix_frame_pointer (fi, 0); + + /* Note if/where callee saved registers were saved. */ + set_movm_offsets (fi, movm_args); + return addr; + } + + /* Note the size of the stack in the frame info structure. */ + stack_size = extract_signed_integer (buf, imm_size); + if (fi) + fi->extra_info->stack_size = stack_size; + + /* We just consumed 2 + imm_size bytes. */ + addr += 2 + imm_size; + + /* No more prologue insns follow, so begin preparation to return. */ + /* Fix fi->frame if it's bogus at this point. */ + fix_frame_pointer (fi, stack_size); + + /* Note if/where callee saved registers were saved. */ + set_movm_offsets (fi, movm_args); + return addr; + } + + /* We never found an insn which allocates local stack space, regardless + this is the end of the prologue. */ + /* Fix fi->frame if it's bogus at this point. */ + fix_frame_pointer (fi, 0); + + /* Note if/where callee saved registers were saved. */ + set_movm_offsets (fi, movm_args); + return addr; +} + +/* Function: frame_chain + Figure out and return the caller's frame pointer given current + frame_info struct. + + We don't handle dummy frames yet but we would probably just return the + stack pointer that was in use at the time the function call was made? */ + +CORE_ADDR +mn10300_frame_chain (fi) + struct frame_info *fi; +{ + struct frame_info *dummy; + /* Walk through the prologue to determine the stack size, + location of saved registers, end of the prologue, etc. */ + if (fi->extra_info->status == 0) + mn10300_analyze_prologue (fi, (CORE_ADDR)0); + + /* Quit now if mn10300_analyze_prologue set NO_MORE_FRAMES. */ + if (fi->extra_info->status & NO_MORE_FRAMES) + return 0; + + /* Now that we've analyzed our prologue, determine the frame + pointer for our caller. + + If our caller has a frame pointer, then we need to + find the entry value of $a3 to our function. + + If fsr.regs[A3_REGNUM] is nonzero, then it's at the memory + location pointed to by fsr.regs[A3_REGNUM]. + + Else it's still in $a3. + + If our caller does not have a frame pointer, then his + frame base is fi->frame + -caller's stack size. */ + + /* The easiest way to get that info is to analyze our caller's frame. + So we set up a dummy frame and call mn10300_analyze_prologue to + find stuff for us. */ + dummy = analyze_dummy_frame (FRAME_SAVED_PC (fi), fi->frame); + + if (dummy->extra_info->status & MY_FRAME_IN_FP) + { + /* Our caller has a frame pointer. So find the frame in $a3 or + in the stack. */ + if (fi->saved_regs[A3_REGNUM]) + return (read_memory_integer (fi->saved_regs[A3_REGNUM], REGISTER_SIZE)); + else + return read_register (A3_REGNUM); + } + else + { + int adjust = 0; + + adjust += (fi->saved_regs[D2_REGNUM] ? 4 : 0); + adjust += (fi->saved_regs[D3_REGNUM] ? 4 : 0); + adjust += (fi->saved_regs[A2_REGNUM] ? 4 : 0); + adjust += (fi->saved_regs[A3_REGNUM] ? 4 : 0); + + /* Our caller does not have a frame pointer. So his frame starts + at the base of our frame (fi->frame) + register save space + + <his size>. */ + return fi->frame + adjust + -dummy->extra_info->stack_size; + } +} + +/* Function: skip_prologue + Return the address of the first inst past the prologue of the function. */ + +CORE_ADDR +mn10300_skip_prologue (pc) + CORE_ADDR pc; +{ + /* We used to check the debug symbols, but that can lose if + we have a null prologue. */ + return mn10300_analyze_prologue (NULL, pc); +} + + +/* Function: pop_frame + This routine gets called when either the user uses the `return' + command, or the call dummy breakpoint gets hit. */ + +void +mn10300_pop_frame (frame) + struct frame_info *frame; +{ + int regnum; + + if (PC_IN_CALL_DUMMY(frame->pc, frame->frame, frame->frame)) + generic_pop_dummy_frame (); + else + { + write_register (PC_REGNUM, FRAME_SAVED_PC (frame)); + + /* Restore any saved registers. */ + for (regnum = 0; regnum < NUM_REGS; regnum++) + if (frame->saved_regs[regnum] != 0) + { + ULONGEST value; + + value = read_memory_unsigned_integer (frame->saved_regs[regnum], + REGISTER_RAW_SIZE (regnum)); + write_register (regnum, value); + } + + /* Actually cut back the stack. */ + write_register (SP_REGNUM, FRAME_FP (frame)); + + /* Don't we need to set the PC?!? XXX FIXME. */ + } + + /* Throw away any cached frame information. */ + flush_cached_frames (); +} + +/* Function: push_arguments + Setup arguments for a call to the target. Arguments go in + order on the stack. */ + +CORE_ADDR +mn10300_push_arguments (nargs, args, sp, struct_return, struct_addr) + int nargs; + value_ptr *args; + CORE_ADDR sp; + unsigned char struct_return; + CORE_ADDR struct_addr; +{ + int argnum = 0; + int len = 0; + int stack_offset = 0; + int regsused = struct_return ? 1 : 0; + + /* This should be a nop, but align the stack just in case something + went wrong. Stacks are four byte aligned on the mn10300. */ + sp &= ~3; + + /* Now make space on the stack for the args. + + XXX This doesn't appear to handle pass-by-invisible reference + arguments. */ + for (argnum = 0; argnum < nargs; argnum++) + { + int arg_length = (TYPE_LENGTH (VALUE_TYPE (args[argnum])) + 3) & ~3; + + while (regsused < 2 && arg_length > 0) + { + regsused++; + arg_length -= 4; + } + len += arg_length; + } + + /* Allocate stack space. */ + sp -= len; + + regsused = struct_return ? 1 : 0; + /* Push all arguments onto the stack. */ + for (argnum = 0; argnum < nargs; argnum++) + { + int len; + char *val; + + /* XXX Check this. What about UNIONS? */ + if (TYPE_CODE (VALUE_TYPE (*args)) == TYPE_CODE_STRUCT + && TYPE_LENGTH (VALUE_TYPE (*args)) > 8) + { + /* XXX Wrong, we want a pointer to this argument. */ + len = TYPE_LENGTH (VALUE_TYPE (*args)); + val = (char *)VALUE_CONTENTS (*args); + } + else + { + len = TYPE_LENGTH (VALUE_TYPE (*args)); + val = (char *)VALUE_CONTENTS (*args); + } + + while (regsused < 2 && len > 0) + { + write_register (regsused, extract_unsigned_integer (val, 4)); + val += 4; + len -= 4; + regsused++; + } + + while (len > 0) + { + write_memory (sp + stack_offset, val, 4); + len -= 4; + val += 4; + stack_offset += 4; + } + + args++; + } + + /* Make space for the flushback area. */ + sp -= 8; + return sp; +} + +/* Function: push_return_address (pc) + Set up the return address for the inferior function call. + Needed for targets where we don't actually execute a JSR/BSR instruction */ + +CORE_ADDR +mn10300_push_return_address (pc, sp) + CORE_ADDR pc; + CORE_ADDR sp; +{ + unsigned char buf[4]; + + store_unsigned_integer (buf, 4, CALL_DUMMY_ADDRESS ()); + write_memory (sp - 4, buf, 4); + return sp - 4; +} + +/* Function: store_struct_return (addr,sp) + Store the structure value return address for an inferior function + call. */ + +CORE_ADDR +mn10300_store_struct_return (addr, sp) + CORE_ADDR addr; + CORE_ADDR sp; +{ + /* The structure return address is passed as the first argument. */ + write_register (0, addr); + return sp; +} + +/* Function: frame_saved_pc + Find the caller of this frame. We do this by seeing if RP_REGNUM + is saved in the stack anywhere, otherwise we get it from the + registers. If the inner frame is a dummy frame, return its PC + instead of RP, because that's where "caller" of the dummy-frame + will be found. */ + +CORE_ADDR +mn10300_frame_saved_pc (fi) + struct frame_info *fi; +{ + int adjust = 0; + + adjust += (fi->saved_regs[D2_REGNUM] ? 4 : 0); + adjust += (fi->saved_regs[D3_REGNUM] ? 4 : 0); + adjust += (fi->saved_regs[A2_REGNUM] ? 4 : 0); + adjust += (fi->saved_regs[A3_REGNUM] ? 4 : 0); + + return (read_memory_integer (fi->frame + adjust, REGISTER_SIZE)); +} + +void +get_saved_register (raw_buffer, optimized, addrp, frame, regnum, lval) + char *raw_buffer; + int *optimized; + CORE_ADDR *addrp; + struct frame_info *frame; + int regnum; + enum lval_type *lval; +{ + generic_get_saved_register (raw_buffer, optimized, addrp, + frame, regnum, lval); +} + +/* Function: mn10300_init_extra_frame_info + Setup the frame's frame pointer, pc, and frame addresses for saved + registers. Most of the work is done in mn10300_analyze_prologue(). + + Note that when we are called for the last frame (currently active frame), + that fi->pc and fi->frame will already be setup. However, fi->frame will + be valid only if this routine uses FP. For previous frames, fi-frame will + always be correct. mn10300_analyze_prologue will fix fi->frame if + it's not valid. + + We can be called with the PC in the call dummy under two circumstances. + First, during normal backtracing, second, while figuring out the frame + pointer just prior to calling the target function (see run_stack_dummy). */ + +void +mn10300_init_extra_frame_info (fi) + struct frame_info *fi; +{ + if (fi->next) + fi->pc = FRAME_SAVED_PC (fi->next); + + frame_saved_regs_zalloc (fi); + fi->extra_info = (struct frame_extra_info *) + frame_obstack_alloc (sizeof (struct frame_extra_info)); + + fi->extra_info->status = 0; + fi->extra_info->stack_size = 0; + + mn10300_analyze_prologue (fi, 0); +} + +/* Function: mn10300_virtual_frame_pointer + Return the register that the function uses for a frame pointer, + plus any necessary offset to be applied to the register before + any frame pointer offsets. */ + +void +mn10300_virtual_frame_pointer (pc, reg, offset) + CORE_ADDR pc; + long *reg; + long *offset; +{ + struct frame_info *dummy = analyze_dummy_frame (pc, 0); + /* Set up a dummy frame_info, Analyze the prolog and fill in the + extra info. */ + /* Results will tell us which type of frame it uses. */ + if (dummy->extra_info->status & MY_FRAME_IN_SP) + { + *reg = SP_REGNUM; + *offset = -(dummy->extra_info->stack_size); + } + else + { + *reg = A3_REGNUM; + *offset = 0; + } +} + +/* This can be made more generic later. */ +static void +set_machine_hook (filename) + char *filename; +{ + int i; + + if (bfd_get_mach (exec_bfd) == bfd_mach_mn10300 + || bfd_get_mach (exec_bfd) == 0) + { + mn10300_register_names = mn10300_generic_register_names; + } + +} + +void +_initialize_mn10300_tdep () +{ +/* printf("_initialize_mn10300_tdep\n"); */ + + tm_print_insn = print_insn_mn10300; + + specify_exec_file_hook (set_machine_hook); +} + |