--- /dev/null
+/* Target-dependent code for the Matsushita MN10300 for GDB, the GNU debugger.
+ Prologue analysis module, extracted from mn10300-tdep.c, Oct. 1, 2004.
+
+ Copyright 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004 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 "symtab.h"
+#include "inferior.h"
+#include "gdbcore.h"
+#include "gdb_string.h"
+#include "trad-frame.h"
+#include "mn10300-tdep.h"
+
+enum movm_register_bits {
+ movm_exother_bit = 0x01,
+ movm_exreg1_bit = 0x02,
+ movm_exreg0_bit = 0x04,
+ movm_other_bit = 0x08,
+ movm_a3_bit = 0x10,
+ movm_a2_bit = 0x20,
+ movm_d3_bit = 0x40,
+ movm_d2_bit = 0x80
+};
+
+/* Values for frame_info.status */
+
+enum frame_kind {
+ MY_FRAME_IN_SP = 0x1,
+ MY_FRAME_IN_FP = 0x2,
+ NO_MORE_FRAMES = 0x4
+};
+
+/*
+ * Frame Extra Info:
+ *
+ * status -- actually frame type (SP, FP, or last frame)
+ * stack size -- offset to the next frame
+ *
+ * The former might ultimately be stored in the frame_base.
+ * Seems like there'd be a way to store the later too.
+ *
+ * Temporarily supply empty stub functions as place holders.
+ */
+
+static void
+my_frame_is_in_sp (struct frame_info *fi, void **this_cache)
+{
+ struct trad_frame_cache *cache = mn10300_frame_unwind_cache (fi, this_cache);
+ trad_frame_set_this_base (cache,
+ frame_unwind_register_unsigned (fi,
+ E_SP_REGNUM));
+}
+
+static void
+my_frame_is_in_fp (struct frame_info *fi, void **this_cache)
+{
+ struct trad_frame_cache *cache = mn10300_frame_unwind_cache (fi, this_cache);
+ trad_frame_set_this_base (cache,
+ frame_unwind_register_unsigned (fi,
+ E_A3_REGNUM));
+}
+
+static void
+my_frame_is_last (struct frame_info *fi)
+{
+}
+
+static int
+is_my_frame_in_sp (struct frame_info *fi)
+{
+ return 0;
+}
+
+static int
+is_my_frame_in_fp (struct frame_info *fi)
+{
+ return 0;
+}
+
+static int
+is_my_frame_last (struct frame_info *fi)
+{
+ return 0;
+}
+
+static void
+set_my_stack_size (struct frame_info *fi, CORE_ADDR size)
+{
+}
+
+
+/* Fix fi->frame if it's bogus at this point. This is a helper
+ function for mn10300_analyze_prologue.
+
+ MVS: This later became frame_base_hack, and probably now
+ could just be trad_frame_set_this_base.
+*/
+
+static void
+fix_frame_pointer (struct frame_info *fi, int stack_size)
+{
+#if 0
+ if (fi && get_next_frame (fi) == NULL)
+ {
+ if (is_my_frame_in_sp (fi))
+ deprecated_update_frame_base_hack (fi, read_sp () - stack_size);
+ else if (is_my_frame_in_fp (fi))
+ deprecated_update_frame_base_hack (fi, read_register (E_A3_REGNUM));
+ }
+#endif
+}
+
+
+/* Set offsets of registers saved by movm instruction.
+ This is a helper function for mn10300_analyze_prologue. */
+
+static void
+set_movm_offsets (struct frame_info *fi,
+ void **this_cache,
+ int movm_args)
+{
+ struct trad_frame_cache *cache;
+ int offset = 0;
+ CORE_ADDR base;
+
+ if (cache == NULL || fi == NULL || movm_args == 0)
+ return;
+
+ cache = mn10300_frame_unwind_cache (fi, this_cache);
+ base = trad_frame_get_this_base (cache);
+ if (movm_args & movm_other_bit)
+ {
+ /* The `other' bit leaves a blank area of four bytes at the
+ beginning of its block of saved registers, making it 32 bytes
+ long in total. */
+ trad_frame_set_reg_addr (cache, E_LAR_REGNUM, base + offset + 4);
+ trad_frame_set_reg_addr (cache, E_LIR_REGNUM, base + offset + 8);
+ trad_frame_set_reg_addr (cache, E_MDR_REGNUM, base + offset + 12);
+ trad_frame_set_reg_addr (cache, E_A0_REGNUM + 1, base + offset + 16);
+ trad_frame_set_reg_addr (cache, E_A0_REGNUM, base + offset + 20);
+ trad_frame_set_reg_addr (cache, E_D0_REGNUM + 1, base + offset + 24);
+ trad_frame_set_reg_addr (cache, E_D0_REGNUM, base + offset + 28);
+ offset += 32;
+ }
+
+ if (movm_args & movm_a3_bit)
+ {
+ trad_frame_set_reg_addr (cache, E_A3_REGNUM, base + offset);
+ offset += 4;
+ }
+ if (movm_args & movm_a2_bit)
+ {
+ trad_frame_set_reg_addr (cache, E_A2_REGNUM, base + offset);
+ offset += 4;
+ }
+ if (movm_args & movm_d3_bit)
+ {
+ trad_frame_set_reg_addr (cache, E_D3_REGNUM, base + offset);
+ offset += 4;
+ }
+ if (movm_args & movm_d2_bit)
+ {
+ trad_frame_set_reg_addr (cache, E_D2_REGNUM, base + offset);
+ offset += 4;
+ }
+ if (AM33_MODE)
+ {
+ if (movm_args & movm_exother_bit)
+ {
+ trad_frame_set_reg_addr (cache, E_MCVF_REGNUM, base + offset);
+ trad_frame_set_reg_addr (cache, E_MCRL_REGNUM, base + offset + 4);
+ trad_frame_set_reg_addr (cache, E_MCRH_REGNUM, base + offset + 8);
+ trad_frame_set_reg_addr (cache, E_MDRQ_REGNUM, base + offset + 12);
+ trad_frame_set_reg_addr (cache, E_E1_REGNUM, base + offset + 16);
+ trad_frame_set_reg_addr (cache, E_E0_REGNUM, base + offset + 20);
+ offset += 24;
+ }
+ if (movm_args & movm_exreg1_bit)
+ {
+ trad_frame_set_reg_addr (cache, E_E7_REGNUM, base + offset);
+ trad_frame_set_reg_addr (cache, E_E6_REGNUM, base + offset + 4);
+ trad_frame_set_reg_addr (cache, E_E5_REGNUM, base + offset + 8);
+ trad_frame_set_reg_addr (cache, E_E4_REGNUM, base + offset + 12);
+ offset += 16;
+ }
+ if (movm_args & movm_exreg0_bit)
+ {
+ trad_frame_set_reg_addr (cache, E_E3_REGNUM, base + offset);
+ trad_frame_set_reg_addr (cache, E_E2_REGNUM, base + offset + 4);
+ offset += 8;
+ }
+ }
+ /* The last (or first) thing on the stack will be the PC. */
+ trad_frame_set_reg_addr (cache, E_PC_REGNUM, base + offset);
+ /* Save the SP in the 'traditional' way.
+ This will be the same location where the PC is saved. */
+ trad_frame_set_reg_value (cache, E_SP_REGNUM, base + offset);
+}
+
+/* The main purpose of this file is dealing with prologues to extract
+ information about stack frames and saved registers.
+
+ In gcc/config/mn13000/mn10300.c, the expand_prologue prologue
+ function is pretty readable, and has a nice explanation of how the
+ prologue is generated. The prologues generated by that code will
+ have the following form (NOTE: the current code doesn't handle all
+ this!):
+
+ + If this is an old-style varargs function, then its arguments
+ need to be flushed back to the stack:
+
+ mov d0,(4,sp)
+ mov d1,(4,sp)
+
+ + If we use any of the callee-saved registers, save them now.
+
+ movm [some callee-saved registers],(sp)
+
+ + If we have any floating-point registers to save:
+
+ - Decrement the stack pointer to reserve space for the registers.
+ If the function doesn't need a frame pointer, we may combine
+ this with the adjustment that reserves space for the frame.
+
+ add -SIZE, sp
+
+ - Save the floating-point registers. We have two possible
+ strategies:
+
+ . Save them at fixed offset from the SP:
+
+ fmov fsN,(OFFSETN,sp)
+ fmov fsM,(OFFSETM,sp)
+ ...
+
+ Note that, if OFFSETN happens to be zero, you'll get the
+ different opcode: fmov fsN,(sp)
+
+ . Or, set a0 to the start of the save area, and then use
+ post-increment addressing to save the FP registers.
+
+ mov sp, a0
+ add SIZE, a0
+ fmov fsN,(a0+)
+ fmov fsM,(a0+)
+ ...
+
+ + If the function needs a frame pointer, we set it here.
+
+ mov sp, a3
+
+ + Now we reserve space for the stack frame proper. This could be
+ merged into the `add -SIZE, sp' instruction for FP saves up
+ above, unless we needed to set the frame pointer in the previous
+ step, or the frame is so large that allocating the whole thing at
+ once would put the FP register save slots out of reach of the
+ addressing mode (128 bytes).
+
+ 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 ($a3).
+
+ 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. */
+
+CORE_ADDR
+mn10300_analyze_prologue (struct frame_info *fi,
+ void **this_cache,
+ CORE_ADDR pc)
+{
+ CORE_ADDR func_addr, func_end, addr, stop;
+ long 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.
+
+ Note: kevinb/2003-07-16: We used to do the following here:
+ pc = (fi ? get_frame_pc (fi) : pc);
+ But this is (now) badly broken when called from analyze_dummy_frame().
+ */
+ pc = (pc ? pc : get_frame_pc (fi));
+
+ /* 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)
+ my_frame_is_last (fi);
+ return pc;
+ }
+
+ /* At the start of a function our frame is in the stack pointer. */
+ if (fi)
+ my_frame_is_in_sp (fi, this_cache);
+
+#if 0
+ /* 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 = deprecated_read_memory_nobpt (pc, buf, 2);
+ if (status != 0)
+ return pc;
+
+ /* Note: kevinb/2003-07-16: We shouldn't be making these sorts of
+ changes to the frame in prologue examination code. */
+ /* 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 (get_next_frame (fi) == NULL)
+ deprecated_update_frame_base_hack (fi, read_sp ());
+ return get_frame_pc (fi);
+ }
+
+ /* Similarly if we're stopped on the first insn of a prologue as our
+ frame hasn't been allocated yet. */
+ if (fi && get_frame_pc (fi) == func_addr)
+ {
+ if (get_next_frame (fi) == NULL)
+ deprecated_update_frame_base_hack (fi, read_sp ());
+ return get_frame_pc (fi);
+ }
+#endif
+
+ /* Figure out where to stop scanning. */
+ stop = 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. */
+ if (addr + 2 >= stop
+ || (status = deprecated_read_memory_nobpt (addr, buf, 2)) != 0)
+ {
+ fix_frame_pointer (fi, 0);
+ return addr;
+ }
+
+ /* First see if this insn sets the stack pointer from a register; if
+ so, it's probably the initialization of the stack pointer in _start,
+ so mark this as the bottom-most frame. */
+ if (buf[0] == 0xf2 && (buf[1] & 0xf3) == 0xf0)
+ {
+ if (fi)
+ my_frame_is_last (fi);
+ 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. */
+ movm_args = buf[1];
+
+ 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 && get_next_frame (fi) == NULL)
+ deprecated_update_frame_base_hack (fi, read_sp ());
+
+ /* Note if/where callee saved registers were saved. */
+ set_movm_offsets (fi, this_cache, movm_args);
+ return addr;
+ }
+
+ /* Get the next two bytes so the prologue scan can continue. */
+ status = deprecated_read_memory_nobpt (addr, buf, 2);
+ if (status != 0)
+ {
+ /* Fix fi->frame since it's bogus at this point. */
+ if (fi && get_next_frame (fi) == NULL)
+ deprecated_update_frame_base_hack (fi, read_sp ());
+
+ /* Note if/where callee saved registers were saved. */
+ set_movm_offsets (fi, this_cache, 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)
+ {
+ my_frame_is_in_fp (fi, this_cache);
+ }
+
+ /* 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, this_cache, movm_args);
+ return addr;
+ }
+
+ /* Get two more bytes so scanning can continue. */
+ status = deprecated_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, this_cache, 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. */
+
+ 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 = deprecated_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, this_cache, 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)
+ set_my_stack_size (fi, 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, this_cache, 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, this_cache, movm_args);
+ return addr;
+}
+
+
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