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* alpha-tdep.c: Update copyright years. 

(alpha_next_pc): New function.
(alpha_software_single_step): Ditto.
* config/alpha/tm-alpha.h: Add prototype for
alpha_software_single_step.
This commit is contained in:
Jason Thorpe 2002-01-18 18:00:44 +00:00
parent e771a87134
commit ec32e4bec5
3 changed files with 121 additions and 1 deletions
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8
gdb/ChangeLog
View File

@ -1,3 +1,11 @@
2002-01-18 Jason Thorpe <thorpej@wasabisystems.com>
* alpha-tdep.c: Update copyright years.
(alpha_next_pc): New function.
(alpha_software_single_step): Ditto.
* config/alpha/tm-alpha.h: Add prototype for
alpha_software_single_step.
2002-01-18 Jason Thorpe <thorpej@wasabisystems.com>
* alphabsd-nat.c: Update copyright years.

111
gdb/alpha-tdep.c
View File

@ -1,5 +1,5 @@
/* Target-dependent code for the ALPHA architecture, for GDB, the GNU Debugger.
Copyright 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001
Copyright 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002
Free Software Foundation, Inc.
This file is part of GDB.
@ -1386,6 +1386,115 @@ alpha_call_dummy_address (void)
return SYMBOL_VALUE_ADDRESS (sym) + 4;
}
/* alpha_software_single_step() is called just before we want to resume
the inferior, if we want to single-step it but there is no hardware
or kernel single-step support (NetBSD on Alpha, for example). We find
the target of the coming instruction and breakpoint it.
single_step is also called just after the inferior stops. If we had
set up a simulated single-step, we undo our damage. */
static CORE_ADDR
alpha_next_pc (CORE_ADDR pc)
{
unsigned int insn;
unsigned int op;
int offset;
LONGEST rav;
insn = read_memory_unsigned_integer (pc, sizeof (insn));
/* Opcode is top 6 bits. */
op = (insn >> 26) & 0x3f;
if (op == 0x1a)
{
/* Jump format: target PC is:
RB & ~3 */
return (read_register ((insn >> 16) & 0x1f) & ~3);
}
if ((op & 0x30) == 0x30)
{
/* Branch format: target PC is:
(new PC) + (4 * sext(displacement)) */
if (op == 0x30 || /* BR */
op == 0x34) /* BSR */
{
branch_taken:
offset = (insn & 0x001fffff);
if (offset & 0x00100000)
offset |= 0xffe00000;
offset *= 4;
return (pc + 4 + offset);
}
/* Need to determine if branch is taken; read RA. */
rav = (LONGEST) read_register ((insn >> 21) & 0x1f);
switch (op)
{
case 0x38: /* BLBC */
if ((rav & 1) == 0)
goto branch_taken;
break;
case 0x3c: /* BLBS */
if (rav & 1)
goto branch_taken;
break;
case 0x39: /* BEQ */
if (rav == 0)
goto branch_taken;
break;
case 0x3d: /* BNE */
if (rav != 0)
goto branch_taken;
break;
case 0x3a: /* BLT */
if (rav < 0)
goto branch_taken;
break;
case 0x3b: /* BLE */
if (rav <= 0)
goto branch_taken;
break;
case 0x3f: /* BGT */
if (rav > 0)
goto branch_taken;
break;
case 0x3e: /* BGE */
if (rav >= 0)
goto branch_taken;
break;
}
}
/* Not a branch or branch not taken; target PC is:
pc + 4 */
return (pc + 4);
}
void
alpha_software_single_step (enum target_signal sig, int insert_breakpoints_p)
{
static CORE_ADDR next_pc;
typedef char binsn_quantum[BREAKPOINT_MAX];
static binsn_quantum break_mem;
CORE_ADDR pc;
if (insert_breakpoints_p)
{
pc = read_pc ();
next_pc = alpha_next_pc (pc);
target_insert_breakpoint (next_pc, break_mem);
}
else
{
target_remove_breakpoint (next_pc, break_mem);
write_pc (next_pc);
}
}
void
_initialize_alpha_tdep (void)
{

3
gdb/config/alpha/tm-alpha.h
View File

@ -474,4 +474,7 @@ extern struct frame_info *setup_arbitrary_frame (int, CORE_ADDR *);
extern CORE_ADDR alpha_osf_skip_sigtramp_frame (struct frame_info *,
CORE_ADDR);
/* Single step based on where the current instruction will take us. */
extern void alpha_software_single_step (enum target_signal, int);
#endif /* TM_ALPHA_H */