/* Target-dependent code for the Mitsubishi m32r for GDB, the GNU debugger.
Copyright 1996, 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 "gdbcore.h"
#include "symfile.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 (gcc_p, type)
+ 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 (fi, regaddr)
+ 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 (start_pc, scan_limit,
+ pl_endptr, framelength,
+ fi, fsr)
+ 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;
+
-/* Find end of function prologue */
+ 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 */
+
+/* Function: skip_prologue
+ Find end of function prologue */
CORE_ADDR
m32r_skip_prologue (pc)
{
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 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 */
- if (prologue_start != entry_point_address ())
- prologue_end = fi->pc;
- else
- return 0; /* _start has no frame or prologue */
- 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 + 40; /* We're in the boondocks: allow for */
- /* 16 pushes, an add, and "mv fp,sp" */
-
- prologue_end = min (prologue_end, fi->pc);
-
- /* Now, search the prologue looking for instructions that setup fp, save
- rp (and other regs), adjust sp and such. */
-
- framesize = 0;
- for (current_pc = prologue_start; current_pc < prologue_end; current_pc += 2)
{
- int insn;
- int regno;
-
- insn = read_memory_unsigned_integer (current_pc, 2);
- if (insn & 0x8000) /* Four byte instruction? */
- current_pc += 2;
-
- if ((insn & 0xf0ff) == 0x207f) { /* st reg, @-sp */
- framesize += 4;
- regno = ((insn >> 8) & 0xf);
- if (fsr) /* save_regs offset */
- fsr->regs[regno] = framesize;
- }
- else if ((insn >> 8) == 0x4f) /* addi sp, xx */
- /* add 8 bit sign-extended offset */
- framesize += -((char) (insn & 0xff));
- else if (insn == 0x8faf) /* add3 sp, sp, xxxx */
- /* add 16 bit sign-extended offset */
- 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 */
- insn = read_memory_unsigned_integer (current_pc - 2, 4);
- if (insn & 0x00800000) /* sign extend */
- insn |= 0xff000000; /* negative */
- else
- insn &= 0x00ffffff; /* positive */
- framesize += insn;
- }
- else if (insn == 0x1d8f) { /* mv fp, sp */
- fi->using_frame_pointer = 1; /* fp is now valid */
- break; /* end of stack adjustments */
- }
- else
- break; /* anything else isn't prologue */
+ 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;
}
-/* This function actually figures out the frame address for a given pc and
+/* 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.
-*/
+ examine the prologue. */
void
m32r_init_extra_frame_info (fi)
fi->pc = FRAME_SAVED_PC (fi->next);
memset (fi->fsr.regs, '\000', sizeof fi->fsr.regs);
- fi->using_frame_pointer = 0;
- fi->framesize = m32r_scan_prologue (fi, &fi->fsr);
-#if 0
- if (PC_IN_CALL_DUMMY (fi->pc, NULL, NULL))
- fi->frame = dummy_frame_stack->sp;
- else
-#endif
- if (!fi->next)
- if (fi->using_frame_pointer)
- fi->frame = read_register (FP_REGNUM);
+
+ if (PC_IN_CALL_DUMMY (fi->pc, fi->frame, fi->frame))
+ {
+ /* 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);
+
+ if (!fi->next)
+ if (fi->using_frame_pointer)
+ {
+ fi->frame = read_register (FP_REGNUM);
+ }
+ else
+ fi->frame = read_register (SP_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->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];
+ }
+}
+
+/* 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
+m32r_virtual_frame_pointer (pc, reg, offset)
+ CORE_ADDR pc;
+ long *reg;
+ long *offset;
+{
+ struct frame_info fi;
- 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];
+ /* Set up a dummy frame_info. */
+ fi.next = NULL;
+ fi.prev = NULL;
+ fi.frame = 0;
+ fi.pc = pc;
+
+ /* Analyze the prolog and fill in the extra info. */
+ m32r_init_extra_frame_info (&fi);
+
+
+ /* 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;
{
-#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, we save the frame size when we initialize the frame_info.
- */
+ For m32r, we save the frame size when we initialize the frame_info. */
CORE_ADDR
m32r_frame_chain (fi)
struct frame_info *fi;
{
- CORE_ADDR fn_start;
+ 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 */
+ 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 ()
-{
- 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;
-}
-
-/*
- * MISSING FUNCTION HEADER COMMENT
- */
-
-int
-m32r_pc_in_call_dummy (pc)
+CORE_ADDR
+m32r_push_return_address (pc, sp)
CORE_ADDR pc;
+ CORE_ADDR sp;
{
-#if 0
- return dummy_frame_stack
- && pc >= CALL_DUMMY_ADDRESS ()
- && pc <= CALL_DUMMY_ADDRESS () + DECR_PC_AFTER_BREAK;
-#else
- return 0;
-#endif
+ write_register (RP_REGNUM, CALL_DUMMY_ADDRESS ());
+ return sp;
}
-/* Discard from the stack the innermost frame,
+
+/* Function: pop_frame
+ Discard from the stack the innermost frame,
restoring all saved registers. */
struct frame_info *
{
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. */
+
+CORE_ADDR
+m32r_frame_saved_pc (fi)
+ 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);
+}
- By the time we get here, stack space has been allocated for the args, but
- not for the struct return pointer. */
+/* 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)
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 (dummy, pc, fun, nargs, args, type, gcc_p)
+ 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 (val)
+ 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 ()
{
projects / binutils-gdb.git / blobdiff