| /* Cache and manage the values of registers for GDB, the GNU debugger. |
| Copyright 1986, 1987, 1989, 1991, 1994, 1995, 1996, 1998, 2000, 2001 |
| 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 "inferior.h" |
| #include "target.h" |
| #include "gdbarch.h" |
| #include "gdbcmd.h" |
| #include "regcache.h" |
| #include "gdb_assert.h" |
| |
| /* |
| * DATA STRUCTURE |
| * |
| * Here is the actual register cache. |
| */ |
| |
| /* NOTE: this is a write-through cache. There is no "dirty" bit for |
| recording if the register values have been changed (eg. by the |
| user). Therefore all registers must be written back to the |
| target when appropriate. */ |
| |
| /* REGISTERS contains the cached register values (in target byte order). */ |
| |
| char *registers; |
| |
| /* REGISTER_VALID is 0 if the register needs to be fetched, |
| 1 if it has been fetched, and |
| -1 if the register value was not available. |
| "Not available" means don't try to fetch it again. */ |
| |
| signed char *register_valid; |
| |
| /* The thread/process associated with the current set of registers. |
| For now, -1 is special, and means `no current process'. */ |
| |
| static int registers_pid = -1; |
| |
| /* |
| * FUNCTIONS: |
| */ |
| |
| /* REGISTER_CACHED() |
| |
| Returns 0 if the value is not in the cache (needs fetch). |
| >0 if the value is in the cache. |
| <0 if the value is permanently unavailable (don't ask again). */ |
| |
| int |
| register_cached (int regnum) |
| { |
| return register_valid[regnum]; |
| } |
| |
| /* Record that REGNUM's value is cached if STATE is >0, uncached but |
| fetchable if STATE is 0, and uncached and unfetchable if STATE is <0. */ |
| |
| void |
| set_register_cached (int regnum, int state) |
| { |
| register_valid[regnum] = state; |
| } |
| |
| /* REGISTER_CHANGED |
| |
| invalidate a single register REGNUM in the cache */ |
| void |
| register_changed (int regnum) |
| { |
| set_register_cached (regnum, 0); |
| } |
| |
| /* If REGNUM >= 0, return a pointer to register REGNUM's cache buffer area, |
| else return a pointer to the start of the cache buffer. */ |
| |
| char * |
| register_buffer (int regnum) |
| { |
| if (regnum < 0) |
| return registers; |
| else |
| return ®isters[REGISTER_BYTE (regnum)]; |
| } |
| |
| /* Return whether register REGNUM is a real register. */ |
| |
| static int |
| real_register (int regnum) |
| { |
| return regnum >= 0 && regnum < NUM_REGS; |
| } |
| |
| /* Return whether register REGNUM is a pseudo register. */ |
| |
| static int |
| pseudo_register (int regnum) |
| { |
| return regnum >= NUM_REGS && regnum < NUM_REGS + NUM_PSEUDO_REGS; |
| } |
| |
| /* Fetch register REGNUM into the cache. */ |
| |
| static void |
| fetch_register (int regnum) |
| { |
| if (real_register (regnum)) |
| target_fetch_registers (regnum); |
| else if (pseudo_register (regnum)) |
| FETCH_PSEUDO_REGISTER (regnum); |
| } |
| |
| /* Write register REGNUM cached value to the target. */ |
| |
| static void |
| store_register (int regnum) |
| { |
| if (real_register (regnum)) |
| target_store_registers (regnum); |
| else if (pseudo_register (regnum)) |
| STORE_PSEUDO_REGISTER (regnum); |
| } |
| |
| /* Low level examining and depositing of registers. |
| |
| The caller is responsible for making sure that the inferior is |
| stopped before calling the fetching routines, or it will get |
| garbage. (a change from GDB version 3, in which the caller got the |
| value from the last stop). */ |
| |
| /* REGISTERS_CHANGED () |
| |
| Indicate that registers may have changed, so invalidate the cache. */ |
| |
| void |
| registers_changed (void) |
| { |
| int i; |
| |
| registers_pid = -1; |
| |
| /* Force cleanup of any alloca areas if using C alloca instead of |
| a builtin alloca. This particular call is used to clean up |
| areas allocated by low level target code which may build up |
| during lengthy interactions between gdb and the target before |
| gdb gives control to the user (ie watchpoints). */ |
| alloca (0); |
| |
| for (i = 0; i < NUM_REGS; i++) |
| set_register_cached (i, 0); |
| |
| /* Assume that if all the hardware regs have changed, |
| then so have the pseudo-registers. */ |
| for (i = NUM_REGS; i < NUM_REGS + NUM_PSEUDO_REGS; i++) |
| set_register_cached (i, 0); |
| |
| if (registers_changed_hook) |
| registers_changed_hook (); |
| } |
| |
| /* REGISTERS_FETCHED () |
| |
| Indicate that all registers have been fetched, so mark them all valid. */ |
| |
| |
| void |
| registers_fetched (void) |
| { |
| int i; |
| |
| for (i = 0; i < NUM_REGS; i++) |
| set_register_cached (i, 1); |
| /* Do not assume that the pseudo-regs have also been fetched. |
| Fetching all real regs might not account for all pseudo-regs. */ |
| } |
| |
| /* read_register_bytes and write_register_bytes are generally a *BAD* |
| idea. They are inefficient because they need to check for partial |
| updates, which can only be done by scanning through all of the |
| registers and seeing if the bytes that are being read/written fall |
| inside of an invalid register. [The main reason this is necessary |
| is that register sizes can vary, so a simple index won't suffice.] |
| It is far better to call read_register_gen and write_register_gen |
| if you want to get at the raw register contents, as it only takes a |
| regnum as an argument, and therefore can't do a partial register |
| update. |
| |
| Prior to the recent fixes to check for partial updates, both read |
| and write_register_bytes always checked to see if any registers |
| were stale, and then called target_fetch_registers (-1) to update |
| the whole set. This caused really slowed things down for remote |
| targets. */ |
| |
| /* Copy INLEN bytes of consecutive data from registers |
| starting with the INREGBYTE'th byte of register data |
| into memory at MYADDR. */ |
| |
| void |
| read_register_bytes (int in_start, char *in_buf, int in_len) |
| { |
| int in_end = in_start + in_len; |
| int regnum; |
| char *reg_buf = alloca (MAX_REGISTER_RAW_SIZE); |
| |
| /* See if we are trying to read bytes from out-of-date registers. If so, |
| update just those registers. */ |
| |
| for (regnum = 0; regnum < NUM_REGS + NUM_PSEUDO_REGS; regnum++) |
| { |
| int reg_start; |
| int reg_end; |
| int reg_len; |
| int start; |
| int end; |
| int byte; |
| |
| if (REGISTER_NAME (regnum) == NULL || *REGISTER_NAME (regnum) == '\0') |
| continue; |
| |
| reg_start = REGISTER_BYTE (regnum); |
| reg_len = REGISTER_RAW_SIZE (regnum); |
| reg_end = reg_start + reg_len; |
| |
| if (reg_end <= in_start || in_end <= reg_start) |
| /* The range the user wants to read doesn't overlap with regnum. */ |
| continue; |
| |
| /* Force the cache to fetch the entire register. */ |
| read_register_gen (regnum, reg_buf); |
| |
| /* Legacy note: This function, for some reason, allows a NULL |
| input buffer. If the buffer is NULL, the registers are still |
| fetched, just the final transfer is skipped. */ |
| if (in_buf == NULL) |
| continue; |
| |
| /* start = max (reg_start, in_start) */ |
| if (reg_start > in_start) |
| start = reg_start; |
| else |
| start = in_start; |
| |
| /* end = min (reg_end, in_end) */ |
| if (reg_end < in_end) |
| end = reg_end; |
| else |
| end = in_end; |
| |
| /* Transfer just the bytes common to both IN_BUF and REG_BUF */ |
| for (byte = start; byte < end; byte++) |
| { |
| in_buf[byte - in_start] = reg_buf[byte - reg_start]; |
| } |
| } |
| } |
| |
| /* Read register REGNUM into memory at MYADDR, which must be large |
| enough for REGISTER_RAW_BYTES (REGNUM). Target byte-order. If the |
| register is known to be the size of a CORE_ADDR or smaller, |
| read_register can be used instead. */ |
| |
| static void |
| legacy_read_register_gen (int regnum, char *myaddr) |
| { |
| gdb_assert (regnum >= 0 && regnum < (NUM_REGS + NUM_PSEUDO_REGS)); |
| if (registers_pid != inferior_pid) |
| { |
| registers_changed (); |
| registers_pid = inferior_pid; |
| } |
| |
| if (!register_cached (regnum)) |
| fetch_register (regnum); |
| |
| memcpy (myaddr, register_buffer (regnum), |
| REGISTER_RAW_SIZE (regnum)); |
| } |
| |
| void |
| regcache_read (int rawnum, char *buf) |
| { |
| gdb_assert (rawnum >= 0 && rawnum < NUM_REGS); |
| /* For moment, just use underlying legacy code. Ulgh!!! */ |
| legacy_read_register_gen (rawnum, buf); |
| } |
| |
| void |
| read_register_gen (int regnum, char *buf) |
| { |
| if (! gdbarch_register_read_p (current_gdbarch)) |
| { |
| legacy_read_register_gen (regnum, buf); |
| return; |
| } |
| gdbarch_register_read (current_gdbarch, regnum, buf); |
| } |
| |
| |
| /* Write register REGNUM at MYADDR to the target. MYADDR points at |
| REGISTER_RAW_BYTES(REGNUM), which must be in target byte-order. */ |
| |
| /* Registers we shouldn't try to store. */ |
| #if !defined (CANNOT_STORE_REGISTER) |
| #define CANNOT_STORE_REGISTER(regnum) 0 |
| #endif |
| |
| static void |
| legacy_write_register_gen (int regnum, char *myaddr) |
| { |
| int size; |
| gdb_assert (regnum >= 0 && regnum < (NUM_REGS + NUM_PSEUDO_REGS)); |
| |
| /* On the sparc, writing %g0 is a no-op, so we don't even want to |
| change the registers array if something writes to this register. */ |
| if (CANNOT_STORE_REGISTER (regnum)) |
| return; |
| |
| if (registers_pid != inferior_pid) |
| { |
| registers_changed (); |
| registers_pid = inferior_pid; |
| } |
| |
| size = REGISTER_RAW_SIZE (regnum); |
| |
| /* If we have a valid copy of the register, and new value == old value, |
| then don't bother doing the actual store. */ |
| |
| if (register_cached (regnum) |
| && memcmp (register_buffer (regnum), myaddr, size) == 0) |
| return; |
| |
| if (real_register (regnum)) |
| target_prepare_to_store (); |
| |
| memcpy (register_buffer (regnum), myaddr, size); |
| |
| set_register_cached (regnum, 1); |
| store_register (regnum); |
| } |
| |
| void |
| regcache_write (int rawnum, char *buf) |
| { |
| gdb_assert (rawnum >= 0 && rawnum < NUM_REGS); |
| /* For moment, just use underlying legacy code. Ulgh!!! */ |
| legacy_write_register_gen (rawnum, buf); |
| } |
| |
| void |
| write_register_gen (int regnum, char *buf) |
| { |
| if (! gdbarch_register_write_p (current_gdbarch)) |
| { |
| legacy_write_register_gen (regnum, buf); |
| return; |
| } |
| gdbarch_register_write (current_gdbarch, regnum, buf); |
| } |
| |
| /* Copy INLEN bytes of consecutive data from memory at MYADDR |
| into registers starting with the MYREGSTART'th byte of register data. */ |
| |
| void |
| write_register_bytes (int myregstart, char *myaddr, int inlen) |
| { |
| int myregend = myregstart + inlen; |
| int regnum; |
| |
| target_prepare_to_store (); |
| |
| /* Scan through the registers updating any that are covered by the |
| range myregstart<=>myregend using write_register_gen, which does |
| nice things like handling threads, and avoiding updates when the |
| new and old contents are the same. */ |
| |
| for (regnum = 0; regnum < NUM_REGS + NUM_PSEUDO_REGS; regnum++) |
| { |
| int regstart, regend; |
| |
| regstart = REGISTER_BYTE (regnum); |
| regend = regstart + REGISTER_RAW_SIZE (regnum); |
| |
| /* Is this register completely outside the range the user is writing? */ |
| if (myregend <= regstart || regend <= myregstart) |
| /* do nothing */ ; |
| |
| /* Is this register completely within the range the user is writing? */ |
| else if (myregstart <= regstart && regend <= myregend) |
| write_register_gen (regnum, myaddr + (regstart - myregstart)); |
| |
| /* The register partially overlaps the range being written. */ |
| else |
| { |
| char *regbuf = (char*) alloca (MAX_REGISTER_RAW_SIZE); |
| /* What's the overlap between this register's bytes and |
| those the caller wants to write? */ |
| int overlapstart = max (regstart, myregstart); |
| int overlapend = min (regend, myregend); |
| |
| /* We may be doing a partial update of an invalid register. |
| Update it from the target before scribbling on it. */ |
| read_register_gen (regnum, regbuf); |
| |
| memcpy (registers + overlapstart, |
| myaddr + (overlapstart - myregstart), |
| overlapend - overlapstart); |
| |
| store_register (regnum); |
| } |
| } |
| } |
| |
| |
| /* Return the contents of register REGNUM as an unsigned integer. */ |
| |
| ULONGEST |
| read_register (int regnum) |
| { |
| char *buf = alloca (REGISTER_RAW_SIZE (regnum)); |
| read_register_gen (regnum, buf); |
| return (extract_unsigned_integer (buf, REGISTER_RAW_SIZE (regnum))); |
| } |
| |
| ULONGEST |
| read_register_pid (int regnum, int pid) |
| { |
| int save_pid; |
| CORE_ADDR retval; |
| |
| if (pid == inferior_pid) |
| return read_register (regnum); |
| |
| save_pid = inferior_pid; |
| |
| inferior_pid = pid; |
| |
| retval = read_register (regnum); |
| |
| inferior_pid = save_pid; |
| |
| return retval; |
| } |
| |
| /* Return the contents of register REGNUM as a signed integer. */ |
| |
| LONGEST |
| read_signed_register (int regnum) |
| { |
| void *buf = alloca (REGISTER_RAW_SIZE (regnum)); |
| read_register_gen (regnum, buf); |
| return (extract_signed_integer (buf, REGISTER_RAW_SIZE (regnum))); |
| } |
| |
| LONGEST |
| read_signed_register_pid (int regnum, int pid) |
| { |
| int save_pid; |
| LONGEST retval; |
| |
| if (pid == inferior_pid) |
| return read_signed_register (regnum); |
| |
| save_pid = inferior_pid; |
| |
| inferior_pid = pid; |
| |
| retval = read_signed_register (regnum); |
| |
| inferior_pid = save_pid; |
| |
| return retval; |
| } |
| |
| /* Store VALUE into the raw contents of register number REGNUM. */ |
| |
| void |
| write_register (int regnum, LONGEST val) |
| { |
| void *buf; |
| int size; |
| size = REGISTER_RAW_SIZE (regnum); |
| buf = alloca (size); |
| store_signed_integer (buf, size, (LONGEST) val); |
| write_register_gen (regnum, buf); |
| } |
| |
| void |
| write_register_pid (int regnum, CORE_ADDR val, int pid) |
| { |
| int save_pid; |
| |
| if (pid == inferior_pid) |
| { |
| write_register (regnum, val); |
| return; |
| } |
| |
| save_pid = inferior_pid; |
| |
| inferior_pid = pid; |
| |
| write_register (regnum, val); |
| |
| inferior_pid = save_pid; |
| } |
| |
| /* SUPPLY_REGISTER() |
| |
| Record that register REGNUM contains VAL. This is used when the |
| value is obtained from the inferior or core dump, so there is no |
| need to store the value there. |
| |
| If VAL is a NULL pointer, then it's probably an unsupported register. |
| We just set its value to all zeros. We might want to record this |
| fact, and report it to the users of read_register and friends. */ |
| |
| void |
| supply_register (int regnum, char *val) |
| { |
| #if 1 |
| if (registers_pid != inferior_pid) |
| { |
| registers_changed (); |
| registers_pid = inferior_pid; |
| } |
| #endif |
| |
| set_register_cached (regnum, 1); |
| if (val) |
| memcpy (register_buffer (regnum), val, |
| REGISTER_RAW_SIZE (regnum)); |
| else |
| memset (register_buffer (regnum), '\000', |
| REGISTER_RAW_SIZE (regnum)); |
| |
| /* On some architectures, e.g. HPPA, there are a few stray bits in |
| some registers, that the rest of the code would like to ignore. */ |
| |
| /* NOTE: cagney/2001-03-16: The macro CLEAN_UP_REGISTER_VALUE is |
| going to be deprecated. Instead architectures will leave the raw |
| register value as is and instead clean things up as they pass |
| through the method gdbarch_register_read() clean up the |
| values. */ |
| |
| #ifdef CLEAN_UP_REGISTER_VALUE |
| CLEAN_UP_REGISTER_VALUE (regnum, register_buffer (regnum)); |
| #endif |
| } |
| |
| /* read_pc, write_pc, read_sp, write_sp, read_fp, write_fp, etc. |
| Special handling for registers PC, SP, and FP. */ |
| |
| /* NOTE: cagney/2001-02-18: The functions generic_target_read_pc(), |
| read_pc_pid(), read_pc(), generic_target_write_pc(), |
| write_pc_pid(), write_pc(), generic_target_read_sp(), read_sp(), |
| generic_target_write_sp(), write_sp(), generic_target_read_fp(), |
| read_fp(), generic_target_write_fp(), write_fp will eventually be |
| moved out of the reg-cache into either frame.[hc] or to the |
| multi-arch framework. The are not part of the raw register cache. */ |
| |
| /* This routine is getting awfully cluttered with #if's. It's probably |
| time to turn this into READ_PC and define it in the tm.h file. |
| Ditto for write_pc. |
| |
| 1999-06-08: The following were re-written so that it assumes the |
| existence of a TARGET_READ_PC et.al. macro. A default generic |
| version of that macro is made available where needed. |
| |
| Since the ``TARGET_READ_PC'' et.al. macro is going to be controlled |
| by the multi-arch framework, it will eventually be possible to |
| eliminate the intermediate read_pc_pid(). The client would call |
| TARGET_READ_PC directly. (cagney). */ |
| |
| CORE_ADDR |
| generic_target_read_pc (int pid) |
| { |
| #ifdef PC_REGNUM |
| if (PC_REGNUM >= 0) |
| { |
| CORE_ADDR pc_val = ADDR_BITS_REMOVE ((CORE_ADDR) read_register_pid (PC_REGNUM, pid)); |
| return pc_val; |
| } |
| #endif |
| internal_error (__FILE__, __LINE__, |
| "generic_target_read_pc"); |
| return 0; |
| } |
| |
| CORE_ADDR |
| read_pc_pid (int pid) |
| { |
| int saved_inferior_pid; |
| CORE_ADDR pc_val; |
| |
| /* In case pid != inferior_pid. */ |
| saved_inferior_pid = inferior_pid; |
| inferior_pid = pid; |
| |
| pc_val = TARGET_READ_PC (pid); |
| |
| inferior_pid = saved_inferior_pid; |
| return pc_val; |
| } |
| |
| CORE_ADDR |
| read_pc (void) |
| { |
| return read_pc_pid (inferior_pid); |
| } |
| |
| void |
| generic_target_write_pc (CORE_ADDR pc, int pid) |
| { |
| #ifdef PC_REGNUM |
| if (PC_REGNUM >= 0) |
| write_register_pid (PC_REGNUM, pc, pid); |
| if (NPC_REGNUM >= 0) |
| write_register_pid (NPC_REGNUM, pc + 4, pid); |
| if (NNPC_REGNUM >= 0) |
| write_register_pid (NNPC_REGNUM, pc + 8, pid); |
| #else |
| internal_error (__FILE__, __LINE__, |
| "generic_target_write_pc"); |
| #endif |
| } |
| |
| void |
| write_pc_pid (CORE_ADDR pc, int pid) |
| { |
| int saved_inferior_pid; |
| |
| /* In case pid != inferior_pid. */ |
| saved_inferior_pid = inferior_pid; |
| inferior_pid = pid; |
| |
| TARGET_WRITE_PC (pc, pid); |
| |
| inferior_pid = saved_inferior_pid; |
| } |
| |
| void |
| write_pc (CORE_ADDR pc) |
| { |
| write_pc_pid (pc, inferior_pid); |
| } |
| |
| /* Cope with strage ways of getting to the stack and frame pointers */ |
| |
| CORE_ADDR |
| generic_target_read_sp (void) |
| { |
| #ifdef SP_REGNUM |
| if (SP_REGNUM >= 0) |
| return read_register (SP_REGNUM); |
| #endif |
| internal_error (__FILE__, __LINE__, |
| "generic_target_read_sp"); |
| } |
| |
| CORE_ADDR |
| read_sp (void) |
| { |
| return TARGET_READ_SP (); |
| } |
| |
| void |
| generic_target_write_sp (CORE_ADDR val) |
| { |
| #ifdef SP_REGNUM |
| if (SP_REGNUM >= 0) |
| { |
| write_register (SP_REGNUM, val); |
| return; |
| } |
| #endif |
| internal_error (__FILE__, __LINE__, |
| "generic_target_write_sp"); |
| } |
| |
| void |
| write_sp (CORE_ADDR val) |
| { |
| TARGET_WRITE_SP (val); |
| } |
| |
| CORE_ADDR |
| generic_target_read_fp (void) |
| { |
| #ifdef FP_REGNUM |
| if (FP_REGNUM >= 0) |
| return read_register (FP_REGNUM); |
| #endif |
| internal_error (__FILE__, __LINE__, |
| "generic_target_read_fp"); |
| } |
| |
| CORE_ADDR |
| read_fp (void) |
| { |
| return TARGET_READ_FP (); |
| } |
| |
| void |
| generic_target_write_fp (CORE_ADDR val) |
| { |
| #ifdef FP_REGNUM |
| if (FP_REGNUM >= 0) |
| { |
| write_register (FP_REGNUM, val); |
| return; |
| } |
| #endif |
| internal_error (__FILE__, __LINE__, |
| "generic_target_write_fp"); |
| } |
| |
| void |
| write_fp (CORE_ADDR val) |
| { |
| TARGET_WRITE_FP (val); |
| } |
| |
| /* ARGSUSED */ |
| static void |
| reg_flush_command (char *command, int from_tty) |
| { |
| /* Force-flush the register cache. */ |
| registers_changed (); |
| if (from_tty) |
| printf_filtered ("Register cache flushed.\n"); |
| } |
| |
| |
| static void |
| build_regcache (void) |
| { |
| /* We allocate some extra slop since we do a lot of memcpy's around |
| `registers', and failing-soft is better than failing hard. */ |
| int sizeof_registers = REGISTER_BYTES + /* SLOP */ 256; |
| int sizeof_register_valid = |
| (NUM_REGS + NUM_PSEUDO_REGS) * sizeof (*register_valid); |
| registers = xmalloc (sizeof_registers); |
| memset (registers, 0, sizeof_registers); |
| register_valid = xmalloc (sizeof_register_valid); |
| memset (register_valid, 0, sizeof_register_valid); |
| } |
| |
| void |
| _initialize_regcache (void) |
| { |
| build_regcache (); |
| |
| register_gdbarch_swap (®isters, sizeof (registers), NULL); |
| register_gdbarch_swap (®ister_valid, sizeof (register_valid), NULL); |
| register_gdbarch_swap (NULL, 0, build_regcache); |
| |
| add_com ("flushregs", class_maintenance, reg_flush_command, |
| "Force gdb to flush its register cache (maintainer command)"); |
| } |