/* Target-dependent code for the Mitsubishi m32r for GDB, the GNU debugger.
- Copyright 1996, Free Software Foundation, Inc.
+ Copyright 1996, 2001 Free Software Foundation, Inc.
-This file is part of GDB.
+ 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 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.
+ 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. */
+ 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 "gdb_string.h"
#include "gdbcore.h"
#include "symfile.h"
+#include "regcache.h"
-struct dummy_frame
+/* Function: m32r_use_struct_convention
+ Return nonzero if call_function should allocate stack space for a
+ struct return? */
+int
+m32r_use_struct_convention (int gcc_p, struct type *type)
{
- struct dummy_frame *next;
+ return (TYPE_LENGTH (type) > 8);
+}
- CORE_ADDR fp;
- CORE_ADDR sp;
- CORE_ADDR rp;
- CORE_ADDR pc;
-};
+/* Function: frame_find_saved_regs
+ Return the frame_saved_regs structure for the frame.
+ Doesn't really work for dummy frames, but it does pass back
+ an empty frame_saved_regs, so I guess that's better than total failure */
-void
-m32r_frame_find_saved_regs PARAMS ((struct frame_info *fi,
- struct frame_saved_regs *regaddr))
+void
+m32r_frame_find_saved_regs (struct frame_info *fi,
+ struct frame_saved_regs *regaddr)
{
- *regaddr = fi->fsr;
+ memcpy (regaddr, &fi->fsr, sizeof (struct frame_saved_regs));
}
-static struct dummy_frame *dummy_frame_stack = NULL;
+/* Turn this on if you want to see just how much instruction decoding
+ if being done, its quite a lot
+ */
+#if 0
+static void
+dump_insn (char *commnt, CORE_ADDR pc, int insn)
+{
+ printf_filtered (" %s %08x %08x ",
+ commnt, (unsigned int) pc, (unsigned int) insn);
+ (*tm_print_insn) (pc, &tm_print_insn_info);
+ printf_filtered ("\n");
+}
+#define insn_debug(args) { printf_filtered args; }
+#else
+#define dump_insn(a,b,c) {}
+#define insn_debug(args) {}
+#endif
+
+#define DEFAULT_SEARCH_LIMIT 44
+
+/* Function: scan_prologue
+ This function decodes the target function prologue to determine
+ 1) the size of the stack frame, and 2) which registers are saved on it.
+ It saves the offsets of saved regs in the frame_saved_regs argument,
+ and returns the frame size. */
+
+/*
+ The sequence it currently generates is:
+
+ if (varargs function) { ddi sp,#n }
+ push registers
+ if (additional stack <= 256) { addi sp,#-stack }
+ else if (additional stack < 65k) { add3 sp,sp,#-stack
+
+ } else if (additional stack) {
+ seth sp,#(stack & 0xffff0000)
+ or3 sp,sp,#(stack & 0x0000ffff)
+ sub sp,r4
+ }
+ if (frame pointer) {
+ mv sp,fp
+ }
+
+ These instructions are scheduled like everything else, so you should stop at
+ the first branch instruction.
+
+ */
+
+/* This is required by skip prologue and by m32r_init_extra_frame_info.
+ The results of decoding a prologue should be cached because this
+ thrashing is getting nuts.
+ I am thinking of making a container class with two indexes, name and
+ address. It may be better to extend the symbol table.
+ */
+
+static void
+decode_prologue (CORE_ADDR start_pc, CORE_ADDR scan_limit, CORE_ADDR *pl_endptr, /* var parameter */
+ unsigned long *framelength, struct frame_info *fi,
+ struct frame_saved_regs *fsr)
+{
+ unsigned long framesize;
+ int insn;
+ int op1;
+ int maybe_one_more = 0;
+ CORE_ADDR after_prologue = 0;
+ CORE_ADDR after_stack_adjust = 0;
+ CORE_ADDR current_pc;
+
+
+ framesize = 0;
+ after_prologue = 0;
+ insn_debug (("rd prolog l(%d)\n", scan_limit - current_pc));
+
+ for (current_pc = start_pc; current_pc < scan_limit; current_pc += 2)
+ {
+
+ insn = read_memory_unsigned_integer (current_pc, 2);
+ dump_insn ("insn-1", current_pc, insn); /* MTZ */
+
+ /* If this is a 32 bit instruction, we dont want to examine its
+ immediate data as though it were an instruction */
+ if (current_pc & 0x02)
+ { /* Clear the parallel execution bit from 16 bit instruction */
+ if (maybe_one_more)
+ { /* The last instruction was a branch, usually terminates
+ the series, but if this is a parallel instruction,
+ it may be a stack framing instruction */
+ if (!(insn & 0x8000))
+ {
+ insn_debug (("Really done"));
+ break; /* nope, we are really done */
+ }
+ }
+ insn &= 0x7fff; /* decode this instruction further */
+ }
+ else
+ {
+ if (maybe_one_more)
+ break; /* This isnt the one more */
+ if (insn & 0x8000)
+ {
+ insn_debug (("32 bit insn\n"));
+ if (current_pc == scan_limit)
+ scan_limit += 2; /* extend the search */
+ current_pc += 2; /* skip the immediate data */
+ if (insn == 0x8faf) /* add3 sp, sp, xxxx */
+ /* add 16 bit sign-extended offset */
+ {
+ insn_debug (("stack increment\n"));
+ framesize += -((short) read_memory_unsigned_integer (current_pc, 2));
+ }
+ else
+ {
+ if (((insn >> 8) == 0xe4) && /* ld24 r4, xxxxxx; sub sp, r4 */
+ read_memory_unsigned_integer (current_pc + 2, 2) == 0x0f24)
+ { /* subtract 24 bit sign-extended negative-offset */
+ dump_insn ("insn-2", current_pc + 2, insn);
+ insn = read_memory_unsigned_integer (current_pc - 2, 4);
+ dump_insn ("insn-3(l4)", current_pc - 2, insn);
+ if (insn & 0x00800000) /* sign extend */
+ insn |= 0xff000000; /* negative */
+ else
+ insn &= 0x00ffffff; /* positive */
+ framesize += insn;
+ }
+ }
+ after_prologue = current_pc;
+ continue;
+ }
+ }
+ op1 = insn & 0xf000; /* isolate just the first nibble */
+
+ if ((insn & 0xf0ff) == 0x207f)
+ { /* st reg, @-sp */
+ int regno;
+ insn_debug (("push\n"));
+#if 0 /* No, PUSH FP is not an indication that we will use a frame pointer. */
+ if (((insn & 0xffff) == 0x2d7f) && fi)
+ fi->using_frame_pointer = 1;
+#endif
+ framesize += 4;
+#if 0
+/* Why should we increase the scan limit, just because we did a push?
+ And if there is a reason, surely we would only want to do it if we
+ had already reached the scan limit... */
+ if (current_pc == scan_limit)
+ scan_limit += 2;
+#endif
+ regno = ((insn >> 8) & 0xf);
+ if (fsr) /* save_regs offset */
+ fsr->regs[regno] = framesize;
+ after_prologue = 0;
+ continue;
+ }
+ if ((insn >> 8) == 0x4f) /* addi sp, xx */
+ /* add 8 bit sign-extended offset */
+ {
+ int stack_adjust = (char) (insn & 0xff);
+
+ /* there are probably two of these stack adjustments:
+ 1) A negative one in the prologue, and
+ 2) A positive one in the epilogue.
+ We are only interested in the first one. */
+
+ if (stack_adjust < 0)
+ {
+ framesize -= stack_adjust;
+ after_prologue = 0;
+ /* A frameless function may have no "mv fp, sp".
+ In that case, this is the end of the prologue. */
+ after_stack_adjust = current_pc + 2;
+ }
+ continue;
+ }
+ if (insn == 0x1d8f)
+ { /* mv fp, sp */
+ if (fi)
+ fi->using_frame_pointer = 1; /* fp is now valid */
+ insn_debug (("done fp found\n"));
+ after_prologue = current_pc + 2;
+ break; /* end of stack adjustments */
+ }
+ if (insn == 0x7000) /* Nop looks like a branch, continue explicitly */
+ {
+ insn_debug (("nop\n"));
+ after_prologue = current_pc + 2;
+ continue; /* nop occurs between pushes */
+ }
+ /* End of prolog if any of these are branch instructions */
+ if ((op1 == 0x7000)
+ || (op1 == 0xb000)
+ || (op1 == 0xf000))
+ {
+ after_prologue = current_pc;
+ insn_debug (("Done: branch\n"));
+ maybe_one_more = 1;
+ continue;
+ }
+ /* Some of the branch instructions are mixed with other types */
+ if (op1 == 0x1000)
+ {
+ int subop = insn & 0x0ff0;
+ if ((subop == 0x0ec0) || (subop == 0x0fc0))
+ {
+ insn_debug (("done: jmp\n"));
+ after_prologue = current_pc;
+ maybe_one_more = 1;
+ continue; /* jmp , jl */
+ }
+ }
+ }
+
+ if (current_pc >= scan_limit)
+ {
+ if (pl_endptr)
+ {
+#if 1
+ if (after_stack_adjust != 0)
+ /* We did not find a "mv fp,sp", but we DID find
+ a stack_adjust. Is it safe to use that as the
+ end of the prologue? I just don't know. */
+ {
+ *pl_endptr = after_stack_adjust;
+ if (framelength)
+ *framelength = framesize;
+ }
+ else
+#endif
+ /* We reached the end of the loop without finding the end
+ of the prologue. No way to win -- we should report failure.
+ The way we do that is to return the original start_pc.
+ GDB will set a breakpoint at the start of the function (etc.) */
+ *pl_endptr = start_pc;
+ }
+ return;
+ }
+ if (after_prologue == 0)
+ after_prologue = current_pc;
+
+ insn_debug ((" framesize %d, firstline %08x\n", framesize, after_prologue));
+ if (framelength)
+ *framelength = framesize;
+ if (pl_endptr)
+ *pl_endptr = after_prologue;
+} /* decode_prologue */
-/* Find end of function prologue */
+/* Function: skip_prologue
+ Find end of function prologue */
CORE_ADDR
-m32r_skip_prologue (pc)
- CORE_ADDR pc;
+m32r_skip_prologue (CORE_ADDR pc)
{
CORE_ADDR func_addr, func_end;
struct symtab_and_line sal;
{
sal = find_pc_line (func_addr, 0);
- if (sal.line != 0 && sal.end < func_end)
- return sal.end;
+ if (sal.line != 0 && sal.end <= func_end)
+ {
+
+ insn_debug (("BP after prologue %08x\n", sal.end));
+ func_end = sal.end;
+ }
else
/* Either there's no line info, or the line after the prologue is after
the end of the function. In this case, there probably isn't a
prologue. */
- return pc;
+ {
+ insn_debug (("No line info, line(%x) sal_end(%x) funcend(%x)\n",
+ sal.line, sal.end, func_end));
+ func_end = min (func_end, func_addr + DEFAULT_SEARCH_LIMIT);
+ }
}
-
- /* We can't find the start of this function, so there's nothing we can do. */
- return pc;
+ else
+ func_end = pc + DEFAULT_SEARCH_LIMIT;
+ decode_prologue (pc, func_end, &sal.end, 0, 0, 0);
+ return sal.end;
}
-/* This function decodes the target function prologue to determine
- 1) the size of the stack frame, and 2) which registers are saved on it.
- It saves the offsets of saved regs in the frame_saved_regs argument,
- and returns the frame size.
-*/
-
static unsigned long
-m32r_scan_prologue (fi, fsr)
- struct frame_info *fi;
- struct frame_saved_regs *fsr;
+m32r_scan_prologue (struct frame_info *fi, struct frame_saved_regs *fsr)
{
struct symtab_and_line sal;
CORE_ADDR prologue_start, prologue_end, current_pc;
- unsigned long framesize;
+ unsigned long framesize = 0;
/* this code essentially duplicates skip_prologue,
but we need the start address below. */
{
sal = find_pc_line (prologue_start, 0);
- if (sal.line == 0) /* no line info, use current PC */
- prologue_end = fi->pc;
- else if (sal.end < prologue_end) /* next line begins after fn end */
- prologue_end = sal.end; /* (probably means no prologue) */
+ if (sal.line == 0) /* no line info, use current PC */
+ if (prologue_start == entry_point_address ())
+ return 0;
}
else
- prologue_end = prologue_start + 100; /* We're in the boondocks */
-
+ {
+ prologue_start = fi->pc;
+ prologue_end = prologue_start + 48; /* We're in the boondocks:
+ allow for 16 pushes, an add,
+ and "mv fp,sp" */
+ }
+#if 0
prologue_end = min (prologue_end, fi->pc);
+#endif
+ insn_debug (("fipc(%08x) start(%08x) end(%08x)\n",
+ fi->pc, prologue_start, prologue_end));
+ prologue_end = min (prologue_end, prologue_start + DEFAULT_SEARCH_LIMIT);
+ decode_prologue (prologue_start, prologue_end, &prologue_end, &framesize,
+ fi, fsr);
+ return framesize;
+}
- /* Now, search the prologue looking for instructions that setup fp, save
- rp (and other regs), adjust sp and such. */
+/* Function: init_extra_frame_info
+ This function actually figures out the frame address for a given pc and
+ sp. This is tricky on the m32r because we sometimes don't use an explicit
+ frame pointer, and the previous stack pointer isn't necessarily recorded
+ on the stack. The only reliable way to get this info is to
+ examine the prologue. */
- framesize = 0;
- memset (fsr->regs, '\000', sizeof fsr->regs);
+void
+m32r_init_extra_frame_info (struct frame_info *fi)
+{
+ int reg;
+
+ if (fi->next)
+ fi->pc = FRAME_SAVED_PC (fi->next);
- for (current_pc = prologue_start; current_pc < prologue_end; current_pc += 2)
+ memset (fi->fsr.regs, '\000', sizeof fi->fsr.regs);
+
+ if (PC_IN_CALL_DUMMY (fi->pc, fi->frame, fi->frame))
{
- int insn;
- int regno;
+ /* We need to setup fi->frame here because run_stack_dummy gets it wrong
+ by assuming it's always FP. */
+ fi->frame = generic_read_register_dummy (fi->pc, fi->frame, SP_REGNUM);
+ fi->framesize = 0;
+ return;
+ }
+ else
+ {
+ fi->using_frame_pointer = 0;
+ fi->framesize = m32r_scan_prologue (fi, &fi->fsr);
- insn = read_memory_unsigned_integer (current_pc, 2);
- if (insn & 0x80) /* Four byte instruction? */
- current_pc += 2;
-
- if ((insn & 0xf0ff) == 0x207f) { /* st reg, @-sp */
- framesize += 4;
- regno = ((insn >> 8) & 0xf);
- fsr->regs[regno] = framesize;
- }
- else if ((insn >> 8) == 0x4f) { /* addi sp */
- framesize += -((char) (insn & 0xff)); /* offset */
- break; /* end of stack adjustments */
- }
+ if (!fi->next)
+ if (fi->using_frame_pointer)
+ {
+ fi->frame = read_register (FP_REGNUM);
+ }
+ else
+ fi->frame = read_register (SP_REGNUM);
+ else
+ /* fi->next means this is not the innermost frame */ if (fi->using_frame_pointer)
+ /* we have an FP */
+ if (fi->next->fsr.regs[FP_REGNUM] != 0) /* caller saved our FP */
+ fi->frame = read_memory_integer (fi->next->fsr.regs[FP_REGNUM], 4);
+ for (reg = 0; reg < NUM_REGS; reg++)
+ if (fi->fsr.regs[reg] != 0)
+ fi->fsr.regs[reg] = fi->frame + fi->framesize - fi->fsr.regs[reg];
}
- return framesize;
}
-/* This function actually figures out the frame address for a given pc and
- sp. This is tricky on the v850 because we only use an explicit frame
- pointer when using alloca(). The only reliable way to get this info is to
- examine the prologue.
-*/
+/* Function: m32r_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
-m32r_init_extra_frame_info (fi)
- struct frame_info *fi;
+m32r_virtual_frame_pointer (CORE_ADDR pc, long *reg, long *offset)
{
- int reg;
- int framesize;
+ struct frame_info fi;
- if (fi->next)
- fi->pc = FRAME_SAVED_PC (fi->next);
+ /* Set up a dummy frame_info. */
+ fi.next = NULL;
+ fi.prev = NULL;
+ fi.frame = 0;
+ fi.pc = pc;
- framesize = m32r_scan_prologue (fi, &fi->fsr);
+ /* Analyze the prolog and fill in the extra info. */
+ m32r_init_extra_frame_info (&fi);
- if (PC_IN_CALL_DUMMY (fi->pc, NULL, NULL))
- fi->frame = dummy_frame_stack->sp;
- else if (!fi->next)
- fi->frame = read_register (SP_REGNUM);
- for (reg = 0; reg < NUM_REGS; reg++)
- if (fi->fsr.regs[reg] != 0)
- fi->fsr.regs[reg] = fi->frame + framesize - fi->fsr.regs[reg];
+ /* Results will tell us which type of frame it uses. */
+ if (fi.using_frame_pointer)
+ {
+ *reg = FP_REGNUM;
+ *offset = 0;
+ }
+ else
+ {
+ *reg = SP_REGNUM;
+ *offset = 0;
+ }
}
-/* 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. */
+/* Function: find_callers_reg
+ Find REGNUM on the stack. Otherwise, it's in an active register. One thing
+ we might want to do here is to check REGNUM against the clobber mask, and
+ somehow flag it as invalid if it isn't saved on the stack somewhere. This
+ would provide a graceful failure mode when trying to get the value of
+ caller-saves registers for an inner frame. */
CORE_ADDR
-m32r_find_callers_reg (fi, regnum)
- struct frame_info *fi;
- int regnum;
+m32r_find_callers_reg (struct frame_info *fi, int regnum)
{
-#if 0
- /* XXX - Won't work if multiple dummy frames are active */
- if (PC_IN_CALL_DUMMY (fi->pc, NULL, NULL))
- switch (regnum)
- {
- case SP_REGNUM:
- return dummy_frame_stack->sp;
- break;
- case FP_REGNUM:
- return dummy_frame_stack->fp;
- break;
- case RP_REGNUM:
- return dummy_frame_stack->pc;
- break;
- case PC_REGNUM:
- return dummy_frame_stack->pc;
- break;
- }
-
-#endif
for (; fi; fi = fi->next)
- if (fi->fsr.regs[regnum] != 0)
- return read_memory_integer (fi->fsr.regs[regnum], 4);
+ if (PC_IN_CALL_DUMMY (fi->pc, fi->frame, fi->frame))
+ return generic_read_register_dummy (fi->pc, fi->frame, regnum);
+ else if (fi->fsr.regs[regnum] != 0)
+ return read_memory_integer (fi->fsr.regs[regnum],
+ REGISTER_RAW_SIZE (regnum));
return read_register (regnum);
}
-/* Given a GDB frame, determine the address of the calling function's frame.
+/* Function: frame_chain
+ Given a GDB frame, determine the address of the calling function's frame.
This will be used to create a new GDB frame struct, and then
INIT_EXTRA_FRAME_INFO and INIT_FRAME_PC will be called for the new frame.
- For m32r, simply get the saved FP off the stack.
- */
+ For m32r, we save the frame size when we initialize the frame_info. */
CORE_ADDR
-m32r_frame_chain (fi)
- struct frame_info *fi;
+m32r_frame_chain (struct frame_info *fi)
{
- CORE_ADDR saved_fp = fi->fsr.regs[FP_REGNUM];
-
- if (saved_fp == 0)
- return 0; /* frameless assembly language fn (such as _start) */
-
- return read_memory_integer (saved_fp, 4);
+ CORE_ADDR fn_start, callers_pc, fp;
+
+ /* is this a dummy frame? */
+ if (PC_IN_CALL_DUMMY (fi->pc, fi->frame, fi->frame))
+ return fi->frame; /* dummy frame same as caller's frame */
+
+ /* is caller-of-this a dummy frame? */
+ callers_pc = FRAME_SAVED_PC (fi); /* find out who called us: */
+ fp = m32r_find_callers_reg (fi, FP_REGNUM);
+ if (PC_IN_CALL_DUMMY (callers_pc, fp, fp))
+ return fp; /* dummy frame's frame may bear no relation to ours */
+
+ if (find_pc_partial_function (fi->pc, 0, &fn_start, 0))
+ if (fn_start == entry_point_address ())
+ return 0; /* in _start fn, don't chain further */
+ if (fi->framesize == 0)
+ {
+ printf_filtered ("cannot determine frame size @ %s , pc(%s)\n",
+ paddr (fi->frame),
+ paddr (fi->pc));
+ return 0;
+ }
+ insn_debug (("m32rx frame %08x\n", fi->frame + fi->framesize));
+ return fi->frame + fi->framesize;
}
-/* All we do here is record SP and FP on the call dummy stack */
+/* Function: push_return_address (pc)
+ Set up the return address for the inferior function call.
+ Necessary for targets that don't actually execute a JSR/BSR instruction
+ (ie. when using an empty CALL_DUMMY) */
-void
-m32r_push_dummy_frame ()
+CORE_ADDR
+m32r_push_return_address (CORE_ADDR pc, CORE_ADDR sp)
{
- struct dummy_frame *dummy_frame;
-
- dummy_frame = xmalloc (sizeof (struct dummy_frame));
-
- dummy_frame->fp = read_register (FP_REGNUM);
- dummy_frame->sp = read_register (SP_REGNUM);
- dummy_frame->rp = read_register (RP_REGNUM);
- dummy_frame->pc = read_register (PC_REGNUM);
- dummy_frame->next = dummy_frame_stack;
- dummy_frame_stack = dummy_frame;
+ write_register (RP_REGNUM, CALL_DUMMY_ADDRESS ());
+ return sp;
}
-/*
- * MISSING FUNCTION HEADER COMMENT
- */
-
-int
-m32r_pc_in_call_dummy (pc)
- CORE_ADDR pc;
-{
- return dummy_frame_stack
- && pc >= CALL_DUMMY_ADDRESS ()
- && pc <= CALL_DUMMY_ADDRESS () + DECR_PC_AFTER_BREAK;
-}
-/* Discard from the stack the innermost frame,
+/* Function: pop_frame
+ Discard from the stack the innermost frame,
restoring all saved registers. */
struct frame_info *
-m32r_pop_frame (frame)
- struct frame_info *frame;
+m32r_pop_frame (struct frame_info *frame)
{
int regnum;
-#if 0
- if (PC_IN_CALL_DUMMY (frame->pc, NULL, NULL))
+ if (PC_IN_CALL_DUMMY (frame->pc, frame->frame, frame->frame))
+ generic_pop_dummy_frame ();
+ else
{
- struct dummy_frame *dummy_frame;
-
- dummy_frame = dummy_frame_stack;
- if (!dummy_frame)
- error ("Can't pop dummy frame!");
-
- dummy_frame_stack = dummy_frame->next;
-
- write_register (FP_REGNUM, dummy_frame->fp);
- write_register (SP_REGNUM, dummy_frame->sp);
- write_register (RP_REGNUM, dummy_frame->rp);
- write_register (PC_REGNUM, dummy_frame->pc);
-
- free (dummy_frame);
-
- flush_cached_frames ();
-
- return NULL;
+ for (regnum = 0; regnum < NUM_REGS; regnum++)
+ if (frame->fsr.regs[regnum] != 0)
+ write_register (regnum,
+ read_memory_integer (frame->fsr.regs[regnum], 4));
+
+ write_register (PC_REGNUM, FRAME_SAVED_PC (frame));
+ write_register (SP_REGNUM, read_register (FP_REGNUM));
+ if (read_register (PSW_REGNUM) & 0x80)
+ write_register (SPU_REGNUM, read_register (SP_REGNUM));
+ else
+ write_register (SPI_REGNUM, read_register (SP_REGNUM));
}
-
-#endif
- write_register (PC_REGNUM, FRAME_SAVED_PC (frame));
-
- for (regnum = 0; regnum < NUM_REGS; regnum++)
- if (frame->fsr.regs[regnum] != 0)
- write_register (regnum,
- read_memory_integer (frame->fsr.regs[regnum], 4));
-
- write_register (SP_REGNUM, read_register (FP_REGNUM));
- if (read_register (PSW_REGNUM) & 0x80)
- write_register (SPU_REGNUM, read_register (SP_REGNUM));
- else
- write_register (SPI_REGNUM, read_register (SP_REGNUM));
- /* registers_changed (); */
flush_cached_frames ();
-
return NULL;
}
-/* Put arguments in the right places, and setup return address register (RP) to
- point at a convenient place to put a breakpoint. First four args go in
- R6->R9, subsequent args go into sp + 16 -> sp + ... Structs are passed by
- reference. 64 bit quantities (doubles and long longs) may be split between
- the regs and the stack. When calling a function that returns a struct, a
- pointer to the struct is passed in as a secret first argument (always in R6).
+/* 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. */
- By the time we get here, stack space has been allocated for the args, but
- not for the struct return pointer. */
+CORE_ADDR
+m32r_frame_saved_pc (struct frame_info *fi)
+{
+ if (PC_IN_CALL_DUMMY (fi->pc, fi->frame, fi->frame))
+ return generic_read_register_dummy (fi->pc, fi->frame, PC_REGNUM);
+ else
+ return m32r_find_callers_reg (fi, RP_REGNUM);
+}
+
+/* Function: push_arguments
+ Setup the function arguments for calling a function in the inferior.
+
+ On the Mitsubishi M32R architecture, there are four registers (R0 to R3)
+ which are dedicated for passing function arguments. Up to the first
+ four arguments (depending on size) may go into these registers.
+ The rest go on the stack.
+
+ Arguments that are smaller than 4 bytes will still take up a whole
+ register or a whole 32-bit word on the stack, and will be
+ right-justified in the register or the stack word. This includes
+ chars, shorts, and small aggregate types.
+
+ Arguments of 8 bytes size are split between two registers, if
+ available. If only one register is available, the argument will
+ be split between the register and the stack. Otherwise it is
+ passed entirely on the stack. Aggregate types with sizes between
+ 4 and 8 bytes are passed entirely on the stack, and are left-justified
+ within the double-word (as opposed to aggregates smaller than 4 bytes
+ which are right-justified).
+
+ Aggregates of greater than 8 bytes are first copied onto the stack,
+ and then a pointer to the copy is passed in the place of the normal
+ argument (either in a register if available, or on the stack).
+
+ Functions that must return an aggregate type can return it in the
+ normal return value registers (R0 and R1) if its size is 8 bytes or
+ less. For larger return values, the caller must allocate space for
+ the callee to copy the return value to. A pointer to this space is
+ passed as an implicit first argument, always in R0. */
CORE_ADDR
-m32r_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;
+m32r_push_arguments (int nargs, value_ptr *args, CORE_ADDR sp,
+ unsigned char struct_return, CORE_ADDR struct_addr)
{
+ int stack_offset, stack_alloc;
int argreg;
int argnum;
+ struct type *type;
+ CORE_ADDR regval;
+ char *val;
+ char valbuf[4];
+ int len;
+ int odd_sized_struct;
- argreg = ARG0_REGNUM;
+ /* first force sp to a 4-byte alignment */
+ sp = sp & ~3;
-#if 0
+ argreg = ARG0_REGNUM;
+ /* The "struct return pointer" pseudo-argument goes in R0 */
if (struct_return)
- {
- write_register (argreg++, struct_addr);
- sp -= 4;
- }
+ write_register (argreg++, struct_addr);
- for (argnum = 0; argnum < nargs; argnum++)
- {
- int len;
- char *val;
- char valbuf[4];
+ /* Now make sure there's space on the stack */
+ for (argnum = 0, stack_alloc = 0;
+ argnum < nargs; argnum++)
+ stack_alloc += ((TYPE_LENGTH (VALUE_TYPE (args[argnum])) + 3) & ~3);
+ sp -= stack_alloc; /* make room on stack for args */
- if (TYPE_CODE (VALUE_TYPE (*args)) == TYPE_CODE_STRUCT
- && TYPE_LENGTH (VALUE_TYPE (*args)) > 8)
- {
- store_address (valbuf, 4, VALUE_ADDRESS (*args));
- len = 4;
+
+ /* Now load as many as possible of the first arguments into
+ registers, and push the rest onto the stack. There are 16 bytes
+ in four registers available. Loop thru args from first to last. */
+
+ argreg = ARG0_REGNUM;
+ for (argnum = 0, stack_offset = 0; argnum < nargs; argnum++)
+ {
+ type = VALUE_TYPE (args[argnum]);
+ len = TYPE_LENGTH (type);
+ memset (valbuf, 0, sizeof (valbuf));
+ if (len < 4)
+ { /* value gets right-justified in the register or stack word */
+ memcpy (valbuf + (4 - len),
+ (char *) VALUE_CONTENTS (args[argnum]), len);
val = valbuf;
}
else
+ val = (char *) VALUE_CONTENTS (args[argnum]);
+
+ if (len > 4 && (len & 3) != 0)
+ odd_sized_struct = 1; /* such structs go entirely on stack */
+ else
+ odd_sized_struct = 0;
+ while (len > 0)
{
- len = TYPE_LENGTH (VALUE_TYPE (*args));
- val = (char *)VALUE_CONTENTS (*args);
+ if (argreg > ARGLAST_REGNUM || odd_sized_struct)
+ { /* must go on the stack */
+ write_memory (sp + stack_offset, val, 4);
+ stack_offset += 4;
+ }
+ /* NOTE WELL!!!!! This is not an "else if" clause!!!
+ That's because some *&^%$ things get passed on the stack
+ AND in the registers! */
+ if (argreg <= ARGLAST_REGNUM)
+ { /* there's room in a register */
+ regval = extract_address (val, REGISTER_RAW_SIZE (argreg));
+ write_register (argreg++, regval);
+ }
+ /* Store the value 4 bytes at a time. This means that things
+ larger than 4 bytes may go partly in registers and partly
+ on the stack. */
+ len -= REGISTER_RAW_SIZE (argreg);
+ val += REGISTER_RAW_SIZE (argreg);
}
+ }
+ return sp;
+}
- while (len > 0)
- if (argreg <= ARGLAST_REGNUM)
- {
- CORE_ADDR regval;
+/* Function: fix_call_dummy
+ If there is real CALL_DUMMY code (eg. on the stack), this function
+ has the responsability to insert the address of the actual code that
+ is the target of the target function call. */
- regval = extract_address (val, REGISTER_RAW_SIZE (argreg));
- write_register (argreg, regval);
+void
+m32r_fix_call_dummy (char *dummy, CORE_ADDR pc, CORE_ADDR fun, int nargs,
+ value_ptr *args, struct type *type, int gcc_p)
+{
+ /* ld24 r8, <(imm24) fun> */
+ *(unsigned long *) (dummy) = (fun & 0x00ffffff) | 0xe8000000;
+}
- len -= REGISTER_RAW_SIZE (argreg);
- val += REGISTER_RAW_SIZE (argreg);
- argreg++;
- }
- else
- {
- write_memory (sp + argnum * 4, val, 4);
- len -= 4;
- val += 4;
- }
- args++;
- }
+/* Function: m32r_write_sp
+ Because SP is really a read-only register that mirrors either SPU or SPI,
+ we must actually write one of those two as well, depending on PSW. */
- write_register (RP_REGNUM, entry_point_address ());
+void
+m32r_write_sp (CORE_ADDR val)
+{
+ unsigned long psw = read_register (PSW_REGNUM);
-#endif
- return sp;
+ if (psw & 0x80) /* stack mode: user or interrupt */
+ write_register (SPU_REGNUM, val);
+ else
+ write_register (SPI_REGNUM, val);
+ write_register (SP_REGNUM, val);
}
-\f
+
void
-_initialize_m32r_tdep ()
+_initialize_m32r_tdep (void)
{
tm_print_insn = print_insn_m32r;
}
projects / binutils-gdb.git / blobdiff