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binutils-gdb/gdb/arm-tdep.c
Andrew Cagney 98760eab33 CARP: Convert macro definitions of USE_STRUCT_CONVENTION into target 
specific functions.
1998-11-23 12:35:23 +00:00

1584 lines
45 KiB
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/* Target-dependent code for the Acorn Risc Machine, for GDB, the GNU Debugger.
Copyright (C) 1988, 1989, 1991, 1992, 1993, 1995, 1996, 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 "gdbcmd.h"
#include "gdbcore.h"
#include "symfile.h"
#include "gdb_string.h"
#include "coff/internal.h" /* Internal format of COFF symbols in BFD */
/*
The following macros are actually wrong. Neither arm nor thumb can
or should set the lsb on addr.
The thumb addresses are mod 2, so (addr & 2) would be a good heuristic
to use when checking for thumb (see arm_pc_is_thumb() below).
Unfortunately, something else depends on these (incorrect) macros, so
fixing them actually breaks gdb. I didn't have time to investigate. Z.R.
*/
/* Thumb function addresses are odd (bit 0 is set). Here are some
macros to test, set, or clear bit 0 of addresses. */
#define IS_THUMB_ADDR(addr) ((addr) & 1)
#define MAKE_THUMB_ADDR(addr) ((addr) | 1)
#define UNMAKE_THUMB_ADDR(addr) ((addr) & ~1)
/* Macros to round N up or down to the next A boundary; A must be
a power of two. */
#define ROUND_DOWN(n,a) ((n) & ~((a) - 1))
#define ROUND_UP(n,a) (((n) + (a) - 1) & ~((a) - 1))
/* Should call_function allocate stack space for a struct return? */
/* The system C compiler uses a similar structure return convention to gcc */
int
arm_use_struct_convention (gcc_p, type)
int gcc_p;
struct type *type;
{
return (TYPE_LENGTH (type) > 4);
}
/* Set to true if the 32-bit mode is in use. */
int arm_apcs_32 = 1;
/* Flag set by arm_fix_call_dummy that tells whether the target function
is a Thumb function. This flag is checked by arm_push_arguments.
FIXME: Change the PUSH_ARGUMENTS macro (and its use in valops.c) to
pass the function address as an additional parameter. */
static int target_is_thumb;
/* Flag set by arm_fix_call_dummy that tells whether the calling function
is a Thumb function. This flag is checked by arm_pc_is_thumb
and arm_call_dummy_breakpoint_offset. */
static int caller_is_thumb;
/* Tell if the program counter value in MEMADDR is in a Thumb function. */
int
arm_pc_is_thumb (memaddr)
bfd_vma memaddr;
{
struct minimal_symbol * sym;
CORE_ADDR sp;
/* If bit 0 of the address is set, assume this is a Thumb address. */
if (IS_THUMB_ADDR (memaddr))
return 1;
/* Thumb function have a "special" bit set in minimal symbols */
sym = lookup_minimal_symbol_by_pc (memaddr);
if (sym)
{
return (MSYMBOL_IS_SPECIAL(sym));
}
else
return 0;
}
/* Tell if the program counter value in MEMADDR is in a call dummy that
is being called from a Thumb function. */
int
arm_pc_is_thumb_dummy (memaddr)
bfd_vma memaddr;
{
CORE_ADDR sp = read_sp();
if (PC_IN_CALL_DUMMY (memaddr, sp, sp+64))
return caller_is_thumb;
else
return 0;
}
CORE_ADDR
arm_addr_bits_remove (val)
CORE_ADDR val;
{
if (arm_pc_is_thumb (val))
return (val & (arm_apcs_32 ? 0xfffffffe : 0x03fffffe));
else
return (val & (arm_apcs_32 ? 0xfffffffc : 0x03fffffc));
}
CORE_ADDR
arm_saved_pc_after_call (frame)
struct frame_info *frame;
{
return ADDR_BITS_REMOVE (read_register (LR_REGNUM));
}
/* A typical Thumb prologue looks like this:
push {r7, lr}
add sp, sp, #-28
add r7, sp, #12
Sometimes the latter instruction may be replaced by:
mov r7, sp
*/
static CORE_ADDR
thumb_skip_prologue (pc)
CORE_ADDR pc;
{
CORE_ADDR current_pc;
for (current_pc = pc; current_pc < pc + 20; current_pc += 2)
{
unsigned short insn = read_memory_unsigned_integer (current_pc, 2);
if ( (insn & 0xfe00) != 0xb400 /* push {..., r7, lr} */
&& (insn & 0xff00) != 0xb000 /* add sp, #simm */
&& (insn & 0xff00) != 0xaf00 /* add r7, sp, #imm */
&& insn != 0x466f /* mov r7, sp */
&& (insn & 0xffc0) != 0x4640) /* mov r0-r7, r8-r15 */
break;
}
return current_pc;
}
/* APCS (ARM procedure call standard) defines the following prologue:
mov ip, sp
[stmfd sp!, {a1,a2,a3,a4}]
stmfd sp!, {...,fp,ip,lr,pc}
[stfe f7, [sp, #-12]!]
[stfe f6, [sp, #-12]!]
[stfe f5, [sp, #-12]!]
[stfe f4, [sp, #-12]!]
sub fp, ip, #nn // nn == 20 or 4 depending on second ins
*/
CORE_ADDR
arm_skip_prologue (pc)
CORE_ADDR pc;
{
unsigned long inst;
CORE_ADDR skip_pc;
CORE_ADDR func_addr, func_end;
struct symtab_and_line sal;
/* See what the symbol table says. */
if (find_pc_partial_function (pc, NULL, & func_addr, & func_end))
{
sal = find_pc_line (func_addr, 0);
if (sal.line != 0 && sal.end < func_end)
return sal.end;
}
/* Check if this is Thumb code. */
if (arm_pc_is_thumb (pc))
return thumb_skip_prologue (pc);
/* Can't find the prologue end in the symbol table, try it the hard way
by disassembling the instructions. */
skip_pc = pc;
inst = read_memory_integer (skip_pc, 4);
if (inst != 0xe1a0c00d) /* mov ip, sp */
return pc;
skip_pc += 4;
inst = read_memory_integer (skip_pc, 4);
if ((inst & 0xfffffff0) == 0xe92d0000) /* stmfd sp!,{a1,a2,a3,a4} */
{
skip_pc += 4;
inst = read_memory_integer (skip_pc, 4);
}
if ((inst & 0xfffff800) != 0xe92dd800) /* stmfd sp!,{...,fp,ip,lr,pc} */
return pc;
skip_pc += 4;
inst = read_memory_integer (skip_pc, 4);
/* Any insns after this point may float into the code, if it makes
for better instruction scheduling, so we skip them only if
we find them, but still consdier the function to be frame-ful */
/* We may have either one sfmfd instruction here, or several stfe insns,
depending on the version of floating point code we support. */
if ((inst & 0xffbf0fff) == 0xec2d0200) /* sfmfd fn, <cnt>, [sp]! */
{
skip_pc += 4;
inst = read_memory_integer (skip_pc, 4);
}
else
{
while ((inst & 0xffff8fff) == 0xed6d0103) /* stfe fn, [sp, #-12]! */
{
skip_pc += 4;
inst = read_memory_integer (skip_pc, 4);
}
}
if ((inst & 0xfffff000) == 0xe24cb000) /* sub fp, ip, #nn */
skip_pc += 4;
return skip_pc;
}
/* Function: thumb_scan_prologue (helper function for arm_scan_prologue)
This function decodes a Thumb function prologue to determine:
1) the size of the stack frame
2) which registers are saved on it
3) the offsets of saved regs
4) the offset from the stack pointer to the frame pointer
This information is stored in the "extra" fields of the frame_info.
A typical Thumb function prologue might look like this:
push {r7, lr}
sub sp, #28,
add r7, sp, #12
Which would create this stack frame (offsets relative to FP)
old SP -> 24 stack parameters
20 LR
16 R7
R7 -> 0 local variables (16 bytes)
SP -> -12 additional stack space (12 bytes)
The frame size would thus be 36 bytes, and the frame offset would be
12 bytes. The frame register is R7. */
static void
thumb_scan_prologue (fi)
struct frame_info * fi;
{
CORE_ADDR prologue_start;
CORE_ADDR prologue_end;
CORE_ADDR current_pc;
int saved_reg[16]; /* which register has been copied to register n? */
int i;
if (find_pc_partial_function (fi->pc, NULL, & prologue_start, & prologue_end))
{
struct symtab_and_line 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) */
}
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);
/* Initialize the saved register map. When register H is copied to
register L, we will put H in saved_reg[L]. */
for (i = 0; i < 16; i++)
saved_reg[i] = i;
/* Search the prologue looking for instructions that set up the
frame pointer, adjust the stack pointer, and save registers. */
fi->framesize = 0;
for (current_pc = prologue_start; current_pc < prologue_end; current_pc += 2)
{
unsigned short insn;
int regno;
int offset;
insn = read_memory_unsigned_integer (current_pc, 2);
if ((insn & 0xfe00) == 0xb400) /* push { rlist } */
{
/* Bits 0-7 contain a mask for registers R0-R7. Bit 8 says
whether to save LR (R14). */
int mask = (insn & 0xff) | ((insn & 0x100) << 6);
/* Calculate offsets of saved R0-R7 and LR. */
for (regno = LR_REGNUM; regno >= 0; regno--)
if (mask & (1 << regno))
{
fi->framesize += 4;
fi->fsr.regs[saved_reg[regno]] = -(fi->framesize);
saved_reg[regno] = regno; /* reset saved register map */
}
}
else if ((insn & 0xff00) == 0xb000) /* add sp, #simm */
{
offset = (insn & 0x7f) << 2; /* get scaled offset */
if (insn & 0x80) /* is it signed? */
offset = -offset;
fi->framesize -= offset;
}
else if ((insn & 0xff00) == 0xaf00) /* add r7, sp, #imm */
{
fi->framereg = THUMB_FP_REGNUM;
fi->frameoffset = (insn & 0xff) << 2; /* get scaled offset */
}
else if (insn == 0x466f) /* mov r7, sp */
{
fi->framereg = THUMB_FP_REGNUM;
fi->frameoffset = 0;
saved_reg[THUMB_FP_REGNUM] = SP_REGNUM;
}
else if ((insn & 0xffc0) == 0x4640) /* mov r0-r7, r8-r15 */
{
int lo_reg = insn & 7; /* dest. register (r0-r7) */
int hi_reg = ((insn >> 3) & 7) + 8; /* source register (r8-15) */
saved_reg[lo_reg] = hi_reg; /* remember hi reg was saved */
}
else
break; /* anything else isn't prologue */
}
}
/* Function: check_prologue_cache
Check if prologue for this frame's PC has already been scanned.
If it has, copy the relevant information about that prologue and
return non-zero. Otherwise do not copy anything and return zero.
The information saved in the cache includes:
* the frame register number;
* the size of the stack frame;
* the offsets of saved regs (relative to the old SP); and
* the offset from the stack pointer to the frame pointer
The cache contains only one entry, since this is adequate
for the typical sequence of prologue scan requests we get.
When performing a backtrace, GDB will usually ask to scan
the same function twice in a row (once to get the frame chain,
and once to fill in the extra frame information).
*/
static struct frame_info prologue_cache;
static int
check_prologue_cache (fi)
struct frame_info * fi;
{
int i;
if (fi->pc == prologue_cache.pc)
{
fi->framereg = prologue_cache.framereg;
fi->framesize = prologue_cache.framesize;
fi->frameoffset = prologue_cache.frameoffset;
for (i = 0; i <= NUM_REGS; i++)
fi->fsr.regs[i] = prologue_cache.fsr.regs[i];
return 1;
}
else
return 0;
}
/* Function: save_prologue_cache
Copy the prologue information from fi to the prologue cache.
*/
static void
save_prologue_cache (fi)
struct frame_info * fi;
{
int i;
prologue_cache.pc = fi->pc;
prologue_cache.framereg = fi->framereg;
prologue_cache.framesize = fi->framesize;
prologue_cache.frameoffset = fi->frameoffset;
for (i = 0; i <= NUM_REGS; i++)
prologue_cache.fsr.regs[i] = fi->fsr.regs[i];
}
/* Function: arm_scan_prologue
This function decodes an ARM function prologue to determine:
1) the size of the stack frame
2) which registers are saved on it
3) the offsets of saved regs
4) the offset from the stack pointer to the frame pointer
This information is stored in the "extra" fields of the frame_info.
A typical Arm function prologue might look like this:
mov ip, sp
stmfd sp!, {fp, ip, lr, pc}
sub fp, ip, #4
sub sp, sp, #16
Which would create this stack frame (offsets relative to FP):
IP -> 4 (caller's stack)
FP -> 0 PC (points to address of stmfd instruction + 12 in callee)
-4 LR (return address in caller)
-8 IP (copy of caller's SP)
-12 FP (caller's FP)
SP -> -28 Local variables
The frame size would thus be 32 bytes, and the frame offset would be
28 bytes. */
static void
arm_scan_prologue (fi)
struct frame_info * fi;
{
int regno, sp_offset, fp_offset;
CORE_ADDR prologue_start, prologue_end, current_pc;
/* Check if this function is already in the cache of frame information. */
if (check_prologue_cache (fi))
return;
/* Assume there is no frame until proven otherwise. */
fi->framereg = SP_REGNUM;
fi->framesize = 0;
fi->frameoffset = 0;
/* Check for Thumb prologue. */
if (arm_pc_is_thumb (fi->pc))
{
thumb_scan_prologue (fi);
save_prologue_cache (fi);
return;
}
/* Find the function prologue. If we can't find the function in
the symbol table, peek in the stack frame to find the PC. */
if (find_pc_partial_function (fi->pc, NULL, &prologue_start, &prologue_end))
{
/* Assume the prologue is everything between the first instruction
in the function and the first source line. */
struct symtab_and_line 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) */
}
else
{
/* Get address of the stmfd in the prologue of the callee; the saved
PC is the address of the stmfd + 12. */
prologue_start = (read_memory_integer (fi->frame, 4) & 0x03fffffc) - 12;
prologue_end = prologue_start + 40; /* FIXME: should be big enough */
}
/* Now search the prologue looking for instructions that set up the
frame pointer, adjust the stack pointer, and save registers. */
sp_offset = fp_offset = 0;
for (current_pc = prologue_start; current_pc < prologue_end; current_pc += 4)
{
unsigned int insn = read_memory_unsigned_integer (current_pc, 4);
if ((insn & 0xffff0000) == 0xe92d0000) /* stmfd sp!, {..., r7, lr} */
{
int mask = insn & 0xffff;
/* Calculate offsets of saved registers. */
for (regno = PC_REGNUM; regno >= 0; regno--)
if (mask & (1 << regno))
{
sp_offset -= 4;
fi->fsr.regs[regno] = sp_offset;
}
}
else if ((insn & 0xfffff000) == 0xe24cb000) /* sub fp, ip #n */
{
unsigned imm = insn & 0xff; /* immediate value */
unsigned rot = (insn & 0xf00) >> 7; /* rotate amount */
imm = (imm >> rot) | (imm << (32-rot));
fp_offset = -imm;
fi->framereg = FP_REGNUM;
}
else if ((insn & 0xfffff000) == 0xe24dd000) /* sub sp, sp #n */
{
unsigned imm = insn & 0xff; /* immediate value */
unsigned rot = (insn & 0xf00) >> 7; /* rotate amount */
imm = (imm >> rot) | (imm << (32-rot));
sp_offset -= imm;
}
else if ((insn & 0xffff7fff) == 0xed6d0103) /* stfe f?, [sp, -#c]! */
{
sp_offset -= 12;
regno = F0_REGNUM + ((insn >> 12) & 0x07);
fi->fsr.regs[regno] = sp_offset;
}
else if (insn == 0xe1a0c00d) /* mov ip, sp */
continue;
else
break; /* not a recognized prologue instruction */
}
/* The frame size is just the negative of the offset (from the original SP)
of the last thing thing we pushed on the stack. The frame offset is
[new FP] - [new SP]. */
fi->framesize = -sp_offset;
fi->frameoffset = fp_offset - sp_offset;
save_prologue_cache (fi);
}
/* 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. */
static CORE_ADDR
arm_find_callers_reg (fi, regnum)
struct frame_info * fi;
int regnum;
{
for (; fi; fi = fi->next)
#if 0 /* FIXME: enable this code if we convert to new call dummy scheme. */
if (PC_IN_CALL_DUMMY (fi->pc, fi->frame, fi->frame))
return generic_read_register_dummy (fi->pc, fi->frame, regnum);
else
#endif
if (fi->fsr.regs[regnum] != 0)
return read_memory_integer (fi->fsr.regs[regnum],
REGISTER_RAW_SIZE(regnum));
return read_register (regnum);
}
/* 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 ARM, we save the frame size when we initialize the frame_info.
The original definition of this function was a macro in tm-arm.h:
{ In the case of the ARM, the frame's nominal address is the FP value,
and 12 bytes before comes the saved previous FP value as a 4-byte word. }
#define FRAME_CHAIN(thisframe) \
((thisframe)->pc >= LOWEST_PC ? \
read_memory_integer ((thisframe)->frame - 12, 4) :\
0)
*/
CORE_ADDR
arm_frame_chain (fi)
struct frame_info * fi;
{
#if 0 /* FIXME: enable this code if we convert to new call dummy scheme. */
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 = arm_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 */
#endif
CORE_ADDR caller_pc, fn_start;
struct frame_info caller_fi;
int framereg = fi->framereg;
if (fi->pc < LOWEST_PC)
return 0;
/* If the caller is the startup code, we're at the end of the chain. */
caller_pc = FRAME_SAVED_PC (fi);
if (find_pc_partial_function (caller_pc, 0, &fn_start, 0))
if (fn_start == entry_point_address ())
return 0;
/* If the caller is Thumb and the caller is ARM, or vice versa,
the frame register of the caller is different from ours.
So we must scan the prologue of the caller to determine its
frame register number. */
if (arm_pc_is_thumb (caller_pc) != arm_pc_is_thumb (fi->pc))
{
memset (& caller_fi, 0, sizeof (caller_fi));
caller_fi.pc = caller_pc;
arm_scan_prologue (& caller_fi);
framereg = caller_fi.framereg;
}
/* If the caller used a frame register, return its value.
Otherwise, return the caller's stack pointer. */
if (framereg == FP_REGNUM || framereg == THUMB_FP_REGNUM)
return arm_find_callers_reg (fi, framereg);
else
return fi->frame + fi->framesize;
}
/* Function: init_extra_frame_info
This function actually figures out the frame address for a given pc and
sp. This is tricky 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. */
void
arm_init_extra_frame_info (fi)
struct frame_info * fi;
{
int reg;
if (fi->next)
fi->pc = FRAME_SAVED_PC (fi->next);
memset (fi->fsr.regs, '\000', sizeof fi->fsr.regs);
#if 0 /* FIXME: enable this code if we convert to new call dummy scheme. */
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;
fi->frameoffset = 0;
return;
}
else
#endif
{
arm_scan_prologue (fi);
if (!fi->next) /* this is the innermost frame? */
fi->frame = read_register (fi->framereg);
else /* not the innermost frame */
/* If we have an FP, the callee saved it. */
if (fi->framereg == FP_REGNUM || fi->framereg == THUMB_FP_REGNUM)
if (fi->next->fsr.regs[fi->framereg] != 0)
fi->frame = read_memory_integer (fi->next->fsr.regs[fi->framereg],
4);
/* Calculate actual addresses of saved registers using offsets determined
by arm_scan_prologue. */
for (reg = 0; reg < NUM_REGS; reg++)
if (fi->fsr.regs[reg] != 0)
fi->fsr.regs[reg] += fi->frame + fi->framesize - fi->frameoffset;
}
}
/* Function: frame_saved_pc
Find the caller of this frame. We do this by seeing if LR_REGNUM is saved
in the stack anywhere, otherwise we get it from the registers.
The old definition of this function was a macro:
#define FRAME_SAVED_PC(FRAME) \
ADDR_BITS_REMOVE (read_memory_integer ((FRAME)->frame - 4, 4))
*/
CORE_ADDR
arm_frame_saved_pc (fi)
struct frame_info * fi;
{
#if 0 /* FIXME: enable this code if we convert to new call dummy scheme. */
if (PC_IN_CALL_DUMMY (fi->pc, fi->frame, fi->frame))
return generic_read_register_dummy (fi->pc, fi->frame, PC_REGNUM);
else
#endif
{
CORE_ADDR pc = arm_find_callers_reg (fi, LR_REGNUM);
return IS_THUMB_ADDR (pc) ? UNMAKE_THUMB_ADDR (pc) : pc;
}
}
/* Return the frame address. On ARM, it is R11; on Thumb it is R7.
Examine the Program Status Register to decide which state we're in. */
CORE_ADDR
arm_target_read_fp ()
{
if (read_register (PS_REGNUM) & 0x20) /* Bit 5 is Thumb state bit */
return read_register (THUMB_FP_REGNUM); /* R7 if Thumb */
else
return read_register (FP_REGNUM); /* R11 if ARM */
}
/* Calculate the frame offsets of the saved registers (ARM version). */
void
arm_frame_find_saved_regs (fi, regaddr)
struct frame_info *fi;
struct frame_saved_regs *regaddr;
{
memcpy (regaddr, &fi->fsr, sizeof (struct frame_saved_regs));
}
void
arm_push_dummy_frame ()
{
CORE_ADDR old_sp = read_register (SP_REGNUM);
CORE_ADDR sp = old_sp;
CORE_ADDR fp, prologue_start;
int regnum;
/* Push the two dummy prologue instructions in reverse order,
so that they'll be in the correct low-to-high order in memory. */
/* sub fp, ip, #4 */
sp = push_word (sp, 0xe24cb004);
/* stmdb sp!, {r0-r10, fp, ip, lr, pc} */
prologue_start = sp = push_word (sp, 0xe92ddfff);
/* push a pointer to the dummy prologue + 12, because when
stm instruction stores the PC, it stores the address of the stm
instruction itself plus 12. */
fp = sp = push_word (sp, prologue_start + 12);
sp = push_word (sp, read_register (PC_REGNUM)); /* FIXME: was PS_REGNUM */
sp = push_word (sp, old_sp);
sp = push_word (sp, read_register (FP_REGNUM));
for (regnum = 10; regnum >= 0; regnum --)
sp = push_word (sp, read_register (regnum));
write_register (FP_REGNUM, fp);
write_register (THUMB_FP_REGNUM, fp);
write_register (SP_REGNUM, sp);
}
/* Fix up the call dummy, based on whether the processor is currently
in Thumb or ARM mode, and whether the target function is Thumb
or ARM. There are three different situations requiring three
different dummies:
* ARM calling ARM: uses the call dummy in tm-arm.h, which has already
been copied into the dummy parameter to this function.
* ARM calling Thumb: uses the call dummy in tm-arm.h, but with the
"mov pc,r4" instruction patched to be a "bx r4" instead.
* Thumb calling anything: uses the Thumb dummy defined below, which
works for calling both ARM and Thumb functions.
All three call dummies expect to receive the target function address
in R4, with the low bit set if it's a Thumb function.
*/
void
arm_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;
{
static short thumb_dummy[4] =
{
0xf000, 0xf801, /* bl label */
0xdf18, /* swi 24 */
0x4720, /* label: bx r4 */
};
static unsigned long arm_bx_r4 = 0xe12fff14; /* bx r4 instruction */
/* Set flag indicating whether the current PC is in a Thumb function. */
caller_is_thumb = arm_pc_is_thumb (read_pc());
/* If the target function is Thumb, set the low bit of the function address.
And if the CPU is currently in ARM mode, patch the second instruction
of call dummy to use a BX instruction to switch to Thumb mode. */
target_is_thumb = arm_pc_is_thumb (fun);
if (target_is_thumb)
{
fun |= 1;
if (!caller_is_thumb)
store_unsigned_integer (dummy + 4, sizeof (arm_bx_r4), arm_bx_r4);
}
/* If the CPU is currently in Thumb mode, use the Thumb call dummy
instead of the ARM one that's already been copied. This will
work for both Thumb and ARM target functions. */
if (caller_is_thumb)
{
int i;
char *p = dummy;
int len = sizeof (thumb_dummy) / sizeof (thumb_dummy[0]);
for (i = 0; i < len; i++)
{
store_unsigned_integer (p, sizeof (thumb_dummy[0]), thumb_dummy[i]);
p += sizeof (thumb_dummy[0]);
}
}
/* Put the target address in r4; the call dummy will copy this to the PC. */
write_register (4, fun);
}
/* Return the offset in the call dummy of the instruction that needs
to have a breakpoint placed on it. This is the offset of the 'swi 24'
instruction, which is no longer actually used, but simply acts
as a place-holder now.
This implements the CALL_DUMMY_BREAK_OFFSET macro.
*/
int
arm_call_dummy_breakpoint_offset ()
{
if (caller_is_thumb)
return 4;
else
return 8;
}
CORE_ADDR
arm_push_arguments(nargs, args, sp, struct_return, struct_addr)
int nargs;
value_ptr * args;
CORE_ADDR sp;
int struct_return;
CORE_ADDR struct_addr;
{
int argreg;
int float_argreg;
int argnum;
int stack_offset;
struct stack_arg {
char *val;
int len;
int offset;
};
struct stack_arg *stack_args =
(struct stack_arg*)alloca (nargs * sizeof (struct stack_arg));
int nstack_args = 0;
/* Initialize the integer and float register pointers. */
argreg = A1_REGNUM;
float_argreg = F0_REGNUM;
/* the struct_return pointer occupies the first parameter-passing reg */
if (struct_return)
write_register (argreg++, struct_addr);
/* The offset onto the stack at which we will start copying parameters
(after the registers are used up) begins at 16 in the old ABI.
This leaves room for the "home" area for register parameters. */
stack_offset = REGISTER_SIZE * 4;
/* Process args from left to right. Store as many as allowed in
registers, save the rest to be pushed on the stack */
for(argnum = 0; argnum < nargs; argnum++)
{
char * val;
value_ptr arg = args[argnum];
struct type * arg_type = check_typedef (VALUE_TYPE (arg));
struct type * target_type = TYPE_TARGET_TYPE (arg_type);
int len = TYPE_LENGTH (arg_type);
enum type_code typecode = TYPE_CODE (arg_type);
CORE_ADDR regval;
int newarg;
val = (char *) VALUE_CONTENTS (arg);
/* If the argument is a pointer to a function, and it's a Thumb
function, set the low bit of the pointer. */
if (typecode == TYPE_CODE_PTR
&& target_type != NULL
&& TYPE_CODE (target_type) == TYPE_CODE_FUNC)
{
regval = extract_address (val, len);
if (arm_pc_is_thumb (regval))
store_address (val, len, MAKE_THUMB_ADDR (regval));
}
#define MAPCS_FLOAT 0 /* --mapcs-float not implemented by the compiler yet */
#if MAPCS_FLOAT
/* Up to four floating point arguments can be passed in floating
point registers on ARM (not on Thumb). */
if (typecode == TYPE_CODE_FLT
&& float_argreg <= ARM_LAST_FP_ARG_REGNUM
&& !target_is_thumb)
{
/* This is a floating point value that fits entirely
in a single register. */
regval = extract_address (val, len);
write_register (float_argreg++, regval);
}
else
#endif
{
/* Copy the argument to general registers or the stack in
register-sized pieces. Large arguments are split between
registers and stack. */
while (len > 0)
{
if (argreg <= ARM_LAST_ARG_REGNUM)
{
int partial_len = len < REGISTER_SIZE ? len : REGISTER_SIZE;
regval = extract_address (val, partial_len);
/* It's a simple argument being passed in a general
register. */
write_register (argreg, regval);
argreg++;
len -= partial_len;
val += partial_len;
}
else
{
/* keep for later pushing */
stack_args[nstack_args].val = val;
stack_args[nstack_args++].len = len;
break;
}
}
}
}
/* now do the real stack pushing, process args right to left */
while(nstack_args--)
{
sp -= stack_args[nstack_args].len;
write_memory(sp, stack_args[nstack_args].val,
stack_args[nstack_args].len);
}
/* Return adjusted stack pointer. */
return sp;
}
void
arm_pop_frame ()
{
struct frame_info *frame = get_current_frame();
int regnum;
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 (frame->framereg));
flush_cached_frames ();
}
static void
print_fpu_flags (flags)
int flags;
{
if (flags & (1 << 0)) fputs ("IVO ", stdout);
if (flags & (1 << 1)) fputs ("DVZ ", stdout);
if (flags & (1 << 2)) fputs ("OFL ", stdout);
if (flags & (1 << 3)) fputs ("UFL ", stdout);
if (flags & (1 << 4)) fputs ("INX ", stdout);
putchar ('\n');
}
void
arm_float_info ()
{
register unsigned long status = read_register (FPS_REGNUM);
int type;
type = (status >> 24) & 127;
printf ("%s FPU type %d\n",
(status & (1<<31)) ? "Hardware" : "Software",
type);
fputs ("mask: ", stdout);
print_fpu_flags (status >> 16);
fputs ("flags: ", stdout);
print_fpu_flags (status);
}
static void
arm_othernames ()
{
static int toggle;
static char *original[] = ORIGINAL_REGISTER_NAMES;
static char *extra_crispy[] = ADDITIONAL_REGISTER_NAMES;
memcpy (reg_names, toggle ? extra_crispy : original, sizeof(original));
toggle = !toggle;
}
/* FIXME: Fill in with the 'right thing', see asm
template in arm-convert.s */
void
convert_from_extended (ptr, dbl)
void * ptr;
double * dbl;
{
*dbl = *(double*)ptr;
}
void
convert_to_extended (dbl, ptr)
void * ptr;
double * dbl;
{
*(double*)ptr = *dbl;
}
static int
condition_true (cond, status_reg)
unsigned long cond;
unsigned long status_reg;
{
if (cond == INST_AL || cond == INST_NV)
return 1;
switch (cond)
{
case INST_EQ:
return ((status_reg & FLAG_Z) != 0);
case INST_NE:
return ((status_reg & FLAG_Z) == 0);
case INST_CS:
return ((status_reg & FLAG_C) != 0);
case INST_CC:
return ((status_reg & FLAG_C) == 0);
case INST_MI:
return ((status_reg & FLAG_N) != 0);
case INST_PL:
return ((status_reg & FLAG_N) == 0);
case INST_VS:
return ((status_reg & FLAG_V) != 0);
case INST_VC:
return ((status_reg & FLAG_V) == 0);
case INST_HI:
return ((status_reg & (FLAG_C | FLAG_Z)) == FLAG_C);
case INST_LS:
return ((status_reg & (FLAG_C | FLAG_Z)) != FLAG_C);
case INST_GE:
return (((status_reg & FLAG_N) == 0) == ((status_reg & FLAG_V) == 0));
case INST_LT:
return (((status_reg & FLAG_N) == 0) != ((status_reg & FLAG_V) == 0));
case INST_GT:
return (((status_reg & FLAG_Z) == 0) &&
(((status_reg & FLAG_N) == 0) == ((status_reg & FLAG_V) == 0)));
case INST_LE:
return (((status_reg & FLAG_Z) != 0) ||
(((status_reg & FLAG_N) == 0) != ((status_reg & FLAG_V) == 0)));
}
return 1;
}
#define submask(x) ((1L << ((x) + 1)) - 1)
#define bit(obj,st) (((obj) >> (st)) & 1)
#define bits(obj,st,fn) (((obj) >> (st)) & submask ((fn) - (st)))
#define sbits(obj,st,fn) \
((long) (bits(obj,st,fn) | ((long) bit(obj,fn) * ~ submask (fn - st))))
#define BranchDest(addr,instr) \
((CORE_ADDR) (((long) (addr)) + 8 + (sbits (instr, 0, 23) << 2)))
#define ARM_PC_32 1
static unsigned long
shifted_reg_val (inst, carry, pc_val, status_reg)
unsigned long inst;
int carry;
unsigned long pc_val;
unsigned long status_reg;
{
unsigned long res, shift;
int rm = bits (inst, 0, 3);
unsigned long shifttype = bits (inst, 5, 6);
if (bit(inst, 4))
{
int rs = bits (inst, 8, 11);
shift = (rs == 15 ? pc_val + 8 : read_register (rs)) & 0xFF;
}
else
shift = bits (inst, 7, 11);
res = (rm == 15
? ((pc_val | (ARM_PC_32 ? 0 : status_reg))
+ (bit (inst, 4) ? 12 : 8))
: read_register (rm));
switch (shifttype)
{
case 0: /* LSL */
res = shift >= 32 ? 0 : res << shift;
break;
case 1: /* LSR */
res = shift >= 32 ? 0 : res >> shift;
break;
case 2: /* ASR */
if (shift >= 32) shift = 31;
res = ((res & 0x80000000L)
? ~((~res) >> shift) : res >> shift);
break;
case 3: /* ROR/RRX */
shift &= 31;
if (shift == 0)
res = (res >> 1) | (carry ? 0x80000000L : 0);
else
res = (res >> shift) | (res << (32-shift));
break;
}
return res & 0xffffffff;
}
/* Return number of 1-bits in VAL. */
static int
bitcount (val)
unsigned long val;
{
int nbits;
for (nbits = 0; val != 0; nbits++)
val &= val - 1; /* delete rightmost 1-bit in val */
return nbits;
}
static CORE_ADDR
thumb_get_next_pc (pc)
CORE_ADDR pc;
{
unsigned long pc_val = ((unsigned long)pc) + 4; /* PC after prefetch */
unsigned short inst1 = read_memory_integer (pc, 2);
CORE_ADDR nextpc = pc + 2; /* default is next instruction */
unsigned long offset;
if ((inst1 & 0xff00) == 0xbd00) /* pop {rlist, pc} */
{
CORE_ADDR sp;
/* Fetch the saved PC from the stack. It's stored above
all of the other registers. */
offset = bitcount (bits (inst1, 0, 7)) * REGISTER_SIZE;
sp = read_register (SP_REGNUM);
nextpc = (CORE_ADDR) read_memory_integer (sp + offset, 4);
nextpc = ADDR_BITS_REMOVE (nextpc);
if (nextpc == pc)
error ("Infinite loop detected");
}
else if ((inst1 & 0xf000) == 0xd000) /* conditional branch */
{
unsigned long status = read_register (PS_REGNUM);
unsigned long cond = bits (inst1, 8, 11);
if (cond != 0x0f && condition_true (cond, status)) /* 0x0f = SWI */
nextpc = pc_val + (sbits (inst1, 0, 7) << 1);
}
else if ((inst1 & 0xf800) == 0xe000) /* unconditional branch */
{
nextpc = pc_val + (sbits (inst1, 0, 10) << 1);
}
else if ((inst1 & 0xf800) == 0xf000) /* long branch with link */
{
unsigned short inst2 = read_memory_integer (pc + 2, 2);
offset = (sbits (inst1, 0, 10) << 12) + (bits (inst2, 0, 10) << 1);
nextpc = pc_val + offset;
}
return nextpc;
}
CORE_ADDR
arm_get_next_pc (pc)
CORE_ADDR pc;
{
unsigned long pc_val;
unsigned long this_instr;
unsigned long status;
CORE_ADDR nextpc;
if (arm_pc_is_thumb (pc))
return thumb_get_next_pc (pc);
pc_val = (unsigned long) pc;
this_instr = read_memory_integer (pc, 4);
status = read_register (PS_REGNUM);
nextpc = (CORE_ADDR) (pc_val + 4); /* Default case */
if (condition_true (bits (this_instr, 28, 31), status))
{
switch (bits (this_instr, 24, 27))
{
case 0x0: case 0x1: /* data processing */
case 0x2: case 0x3:
{
unsigned long operand1, operand2, result = 0;
unsigned long rn;
int c;
if (bits (this_instr, 12, 15) != 15)
break;
if (bits (this_instr, 22, 25) == 0
&& bits (this_instr, 4, 7) == 9) /* multiply */
error ("Illegal update to pc in instruction");
/* Multiply into PC */
c = (status & FLAG_C) ? 1 : 0;
rn = bits (this_instr, 16, 19);
operand1 = (rn == 15) ? pc_val + 8 : read_register (rn);
if (bit (this_instr, 25))
{
unsigned long immval = bits (this_instr, 0, 7);
unsigned long rotate = 2 * bits (this_instr, 8, 11);
operand2 = ((immval >> rotate) | (immval << (32-rotate)))
& 0xffffffff;
}
else /* operand 2 is a shifted register */
operand2 = shifted_reg_val (this_instr, c, pc_val, status);
switch (bits (this_instr, 21, 24))
{
case 0x0: /*and*/
result = operand1 & operand2;
break;
case 0x1: /*eor*/
result = operand1 ^ operand2;
break;
case 0x2: /*sub*/
result = operand1 - operand2;
break;
case 0x3: /*rsb*/
result = operand2 - operand1;
break;
case 0x4: /*add*/
result = operand1 + operand2;
break;
case 0x5: /*adc*/
result = operand1 + operand2 + c;
break;
case 0x6: /*sbc*/
result = operand1 - operand2 + c;
break;
case 0x7: /*rsc*/
result = operand2 - operand1 + c;
break;
case 0x8: case 0x9: case 0xa: case 0xb: /* tst, teq, cmp, cmn */
result = (unsigned long) nextpc;
break;
case 0xc: /*orr*/
result = operand1 | operand2;
break;
case 0xd: /*mov*/
/* Always step into a function. */
result = operand2;
break;
case 0xe: /*bic*/
result = operand1 & ~operand2;
break;
case 0xf: /*mvn*/
result = ~operand2;
break;
}
nextpc = (CORE_ADDR) ADDR_BITS_REMOVE (result);
if (nextpc == pc)
error ("Infinite loop detected");
break;
}
case 0x4: case 0x5: /* data transfer */
case 0x6: case 0x7:
if (bit (this_instr, 20))
{
/* load */
if (bits (this_instr, 12, 15) == 15)
{
/* rd == pc */
unsigned long rn;
unsigned long base;
if (bit (this_instr, 22))
error ("Illegal update to pc in instruction");
/* byte write to PC */
rn = bits (this_instr, 16, 19);
base = (rn == 15) ? pc_val + 8 : read_register (rn);
if (bit (this_instr, 24))
{
/* pre-indexed */
int c = (status & FLAG_C) ? 1 : 0;
unsigned long offset =
(bit (this_instr, 25)
? shifted_reg_val (this_instr, c, pc_val)
: bits (this_instr, 0, 11));
if (bit (this_instr, 23))
base += offset;
else
base -= offset;
}
nextpc = (CORE_ADDR) read_memory_integer ((CORE_ADDR) base,
4);
nextpc = ADDR_BITS_REMOVE (nextpc);
if (nextpc == pc)
error ("Infinite loop detected");
}
}
break;
case 0x8: case 0x9: /* block transfer */
if (bit (this_instr, 20))
{
/* LDM */
if (bit (this_instr, 15))
{
/* loading pc */
int offset = 0;
if (bit (this_instr, 23))
{
/* up */
unsigned long reglist = bits (this_instr, 0, 14);
offset = bitcount (reglist) * 4;
if (bit (this_instr, 24)) /* pre */
offset += 4;
}
else if (bit (this_instr, 24))
offset = -4;
{
unsigned long rn_val =
read_register (bits (this_instr, 16, 19));
nextpc =
(CORE_ADDR) read_memory_integer ((CORE_ADDR) (rn_val
+ offset),
4);
}
nextpc = ADDR_BITS_REMOVE (nextpc);
if (nextpc == pc)
error ("Infinite loop detected");
}
}
break;
case 0xb: /* branch & link */
case 0xa: /* branch */
{
nextpc = BranchDest (pc, this_instr);
nextpc = ADDR_BITS_REMOVE (nextpc);
if (nextpc == pc)
error ("Infinite loop detected");
break;
}
case 0xc: case 0xd:
case 0xe: /* coproc ops */
case 0xf: /* SWI */
break;
default:
fprintf (stderr, "Bad bit-field extraction\n");
return (pc);
}
}
return nextpc;
}
#include "bfd-in2.h"
#include "libcoff.h"
static int
gdb_print_insn_arm (memaddr, info)
bfd_vma memaddr;
disassemble_info * info;
{
if (arm_pc_is_thumb (memaddr))
{
static asymbol * asym;
static combined_entry_type ce;
static struct coff_symbol_struct csym;
static struct _bfd fake_bfd;
static bfd_target fake_target;
if (csym.native == NULL)
{
/* Create a fake symbol vector containing a Thumb symbol. This is
solely so that the code in print_insn_little_arm() and
print_insn_big_arm() in opcodes/arm-dis.c will detect the presence
of a Thumb symbol and switch to decoding Thumb instructions. */
fake_target.flavour = bfd_target_coff_flavour;
fake_bfd.xvec = & fake_target;
ce.u.syment.n_sclass = C_THUMBEXTFUNC;
csym.native = & ce;
csym.symbol.the_bfd = & fake_bfd;
csym.symbol.name = "fake";
asym = (asymbol *) & csym;
}
memaddr = UNMAKE_THUMB_ADDR (memaddr);
info->symbols = & asym;
}
else
info->symbols = NULL;
if (TARGET_BYTE_ORDER == BIG_ENDIAN)
return print_insn_big_arm (memaddr, info);
else
return print_insn_little_arm (memaddr, info);
}
/* This function implements the BREAKPOINT_FROM_PC macro. It uses the program
counter value to determine whether a 16- or 32-bit breakpoint should be
used. It returns a pointer to a string of bytes that encode a breakpoint
instruction, stores the length of the string to *lenptr, and adjusts pc
(if necessary) to point to the actual memory location where the
breakpoint should be inserted. */
unsigned char *
arm_breakpoint_from_pc (pcptr, lenptr)
CORE_ADDR * pcptr;
int * lenptr;
{
if (arm_pc_is_thumb (*pcptr) || arm_pc_is_thumb_dummy (*pcptr))
{
if (TARGET_BYTE_ORDER == BIG_ENDIAN)
{
static char thumb_breakpoint[] = THUMB_BE_BREAKPOINT;
*pcptr = UNMAKE_THUMB_ADDR (*pcptr);
*lenptr = sizeof (thumb_breakpoint);
return thumb_breakpoint;
}
else
{
static char thumb_breakpoint[] = THUMB_LE_BREAKPOINT;
*pcptr = UNMAKE_THUMB_ADDR (*pcptr);
*lenptr = sizeof (thumb_breakpoint);
return thumb_breakpoint;
}
}
else
{
if (TARGET_BYTE_ORDER == BIG_ENDIAN)
{
static char arm_breakpoint[] = ARM_BE_BREAKPOINT;
*lenptr = sizeof (arm_breakpoint);
return arm_breakpoint;
}
else
{
static char arm_breakpoint[] = ARM_LE_BREAKPOINT;
*lenptr = sizeof (arm_breakpoint);
return arm_breakpoint;
}
}
}
/* Return non-zero if the PC is inside a call thunk (aka stub or trampoline).
This implements the IN_SOLIB_CALL_TRAMPOLINE macro. */
int
arm_in_call_stub (pc, name)
CORE_ADDR pc;
char * name;
{
CORE_ADDR start_addr;
/* Find the starting address of the function containing the PC. If the
caller didn't give us a name, look it up at the same time. */
if (find_pc_partial_function (pc, name ? NULL : &name, &start_addr, NULL) == 0)
return 0;
return strncmp (name, "_call_via_r", 11) == 0;
}
/* If PC is in a Thumb call or return stub, return the address of the target
PC, which is in a register. The thunk functions are called _called_via_xx,
where x is the register name. The possible names are r0-r9, sl, fp, ip,
sp, and lr. */
CORE_ADDR
arm_skip_stub (pc)
CORE_ADDR pc;
{
char * name;
CORE_ADDR start_addr;
/* Find the starting address and name of the function containing the PC. */
if (find_pc_partial_function (pc, &name, &start_addr, NULL) == 0)
return 0;
/* Call thunks always start with "_call_via_". */
if (strncmp (name, "_call_via_", 10) == 0)
{
/* Use the name suffix to determine which register contains
the target PC. */
static char *table[15] =
{ "r0", "r1", "r2", "r3", "r4", "r5", "r6", "r7",
"r8", "r9", "sl", "fp", "ip", "sp", "lr"
};
int regno;
for (regno = 0; regno <= 14; regno++)
if (strcmp (&name[10], table[regno]) == 0)
return read_register (regno);
}
return 0; /* not a stub */
}
void
_initialize_arm_tdep ()
{
tm_print_insn = gdb_print_insn_arm;
add_com ("othernames", class_obscure, arm_othernames,
"Switch to the other set of register names.");
/* ??? Maybe this should be a boolean. */
add_show_from_set (add_set_cmd ("apcs32", no_class,
var_zinteger, (char *)&arm_apcs_32,
"Set usage of ARM 32-bit mode.\n", &setlist),
& showlist);
}
/* Test whether the coff symbol specific value corresponds to a Thumb function */
int
coff_sym_is_thumb(int val)
{
return (val == C_THUMBEXT ||
val == C_THUMBSTAT ||
val == C_THUMBEXTFUNC ||
val == C_THUMBSTATFUNC ||
val == C_THUMBLABEL);
}
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