| /* Target-dependent code for the Fujitsu FR30. |
| Copyright 1999, 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 "frame.h" |
| #include "inferior.h" |
| #include "obstack.h" |
| #include "target.h" |
| #include "value.h" |
| #include "bfd.h" |
| #include "gdb_string.h" |
| #include "gdbcore.h" |
| #include "symfile.h" |
| #include "regcache.h" |
| |
| /* An expression that tells us whether the function invocation represented |
| by FI does not have a frame on the stack associated with it. */ |
| int |
| fr30_frameless_function_invocation (struct frame_info *fi) |
| { |
| int frameless; |
| CORE_ADDR func_start, after_prologue; |
| func_start = (get_pc_function_start ((fi)->pc) + |
| FUNCTION_START_OFFSET); |
| after_prologue = func_start; |
| after_prologue = SKIP_PROLOGUE (after_prologue); |
| frameless = (after_prologue == func_start); |
| return frameless; |
| } |
| |
| /* Function: pop_frame |
| This routine gets called when either the user uses the `return' |
| command, or the call dummy breakpoint gets hit. */ |
| |
| void |
| fr30_pop_frame (void) |
| { |
| struct frame_info *frame = get_current_frame (); |
| int regnum; |
| CORE_ADDR sp = read_register (SP_REGNUM); |
| |
| if (PC_IN_CALL_DUMMY (frame->pc, frame->frame, frame->frame)) |
| generic_pop_dummy_frame (); |
| else |
| { |
| 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_unsigned_integer (frame->fsr.regs[regnum], |
| REGISTER_RAW_SIZE (regnum))); |
| } |
| write_register (SP_REGNUM, sp + frame->framesize); |
| } |
| flush_cached_frames (); |
| } |
| |
| |
| /* Function: fr30_store_return_value |
| Put a value where a caller expects to see it. Used by the 'return' |
| command. */ |
| void |
| fr30_store_return_value (struct type *type, |
| char *valbuf) |
| { |
| /* Here's how the FR30 returns values (gleaned from gcc/config/ |
| fr30/fr30.h): |
| |
| If the return value is 32 bits long or less, it goes in r4. |
| |
| If the return value is 64 bits long or less, it goes in r4 (most |
| significant word) and r5 (least significant word. |
| |
| If the function returns a structure, of any size, the caller |
| passes the function an invisible first argument where the callee |
| should store the value. But GDB doesn't let you do that anyway. |
| |
| If you're returning a value smaller than a word, it's not really |
| necessary to zero the upper bytes of the register; the caller is |
| supposed to ignore them. However, the FR30 typically keeps its |
| values extended to the full register width, so we should emulate |
| that. */ |
| |
| /* The FR30 is big-endian, so if we return a small value (like a |
| short or a char), we need to position it correctly within the |
| register. We round the size up to a register boundary, and then |
| adjust the offset so as to place the value at the right end. */ |
| int value_size = TYPE_LENGTH (type); |
| int returned_size = (value_size + FR30_REGSIZE - 1) & ~(FR30_REGSIZE - 1); |
| int offset = (REGISTER_BYTE (RETVAL_REG) |
| + (returned_size - value_size)); |
| char *zeros = alloca (returned_size); |
| memset (zeros, 0, returned_size); |
| |
| write_register_bytes (REGISTER_BYTE (RETVAL_REG), zeros, returned_size); |
| write_register_bytes (offset, valbuf, value_size); |
| } |
| |
| |
| /* Function: skip_prologue |
| Return the address of the first code past the prologue of the function. */ |
| |
| CORE_ADDR |
| fr30_skip_prologue (CORE_ADDR pc) |
| { |
| CORE_ADDR func_addr, func_end; |
| |
| /* See what the symbol table says */ |
| |
| if (find_pc_partial_function (pc, NULL, &func_addr, &func_end)) |
| { |
| struct symtab_and_line sal; |
| |
| sal = find_pc_line (func_addr, 0); |
| |
| if (sal.line != 0 && sal.end < func_end) |
| { |
| return sal.end; |
| } |
| } |
| |
| /* Either we didn't find the start of this function (nothing we can do), |
| or there's no line info, or the line after the prologue is after |
| the end of the function (there probably isn't a prologue). */ |
| |
| return pc; |
| } |
| |
| |
| /* Function: push_arguments |
| Setup arguments and RP for a call to the target. First four args |
| go in FIRST_ARGREG -> LAST_ARGREG, subsequent args go on stack... |
| Structs are passed by reference. XXX not right now Z.R. |
| 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 FIRST_ARGREG). |
| |
| Stack space for the args has NOT been allocated: that job is up to us. |
| */ |
| |
| CORE_ADDR |
| fr30_push_arguments (int nargs, struct value **args, CORE_ADDR sp, |
| int struct_return, CORE_ADDR struct_addr) |
| { |
| int 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; |
| |
| argreg = FIRST_ARGREG; |
| |
| /* the struct_return pointer occupies the first parameter-passing reg */ |
| if (struct_return) |
| write_register (argreg++, struct_addr); |
| |
| stack_offset = 0; |
| |
| /* 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; |
| struct value *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); |
| |
| { |
| /* 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 <= LAST_ARGREG) |
| { |
| 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 _initialize_fr30_tdep (void); |
| |
| void |
| _initialize_fr30_tdep (void) |
| { |
| extern int print_insn_fr30 (bfd_vma, disassemble_info *); |
| tm_print_insn = print_insn_fr30; |
| } |
| |
| /* 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 (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 (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: scan_prologue |
| Scan the prologue of the function that contains PC, and record what |
| we find in PI. PI->fsr must be zeroed by the called. Returns the |
| pc after the prologue. Note that the addresses saved in pi->fsr |
| are actually just frame relative (negative offsets from the frame |
| pointer). This is because we don't know the actual value of the |
| frame pointer yet. In some circumstances, the frame pointer can't |
| be determined till after we have scanned the prologue. */ |
| |
| static void |
| fr30_scan_prologue (struct frame_info *fi) |
| { |
| int 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; |
| |
| /* 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 |
| { |
| /* XXX Z.R. What now??? The following is entirely bogus */ |
| prologue_start = (read_memory_integer (fi->frame, 4) & 0x03fffffc) - 12; |
| prologue_end = prologue_start + 40; |
| } |
| |
| /* 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 += 2) |
| { |
| unsigned int insn; |
| |
| insn = read_memory_unsigned_integer (current_pc, 2); |
| |
| if ((insn & 0xfe00) == 0x8e00) /* stm0 or stm1 */ |
| { |
| int reg, mask = insn & 0xff; |
| |
| /* scan in one sweep - create virtual 16-bit mask from either insn's mask */ |
| if ((insn & 0x0100) == 0) |
| { |
| mask <<= 8; /* stm0 - move to upper byte in virtual mask */ |
| } |
| |
| /* Calculate offsets of saved registers (to be turned later into addresses). */ |
| for (reg = R4_REGNUM; reg <= R11_REGNUM; reg++) |
| if (mask & (1 << (15 - reg))) |
| { |
| sp_offset -= 4; |
| fi->fsr.regs[reg] = sp_offset; |
| } |
| } |
| else if ((insn & 0xfff0) == 0x1700) /* st rx,@-r15 */ |
| { |
| int reg = insn & 0xf; |
| |
| sp_offset -= 4; |
| fi->fsr.regs[reg] = sp_offset; |
| } |
| else if ((insn & 0xff00) == 0x0f00) /* enter */ |
| { |
| fp_offset = fi->fsr.regs[FP_REGNUM] = sp_offset - 4; |
| sp_offset -= 4 * (insn & 0xff); |
| fi->framereg = FP_REGNUM; |
| } |
| else if (insn == 0x1781) /* st rp,@-sp */ |
| { |
| sp_offset -= 4; |
| fi->fsr.regs[RP_REGNUM] = sp_offset; |
| } |
| else if (insn == 0x170e) /* st fp,@-sp */ |
| { |
| sp_offset -= 4; |
| fi->fsr.regs[FP_REGNUM] = sp_offset; |
| } |
| else if (insn == 0x8bfe) /* mov sp,fp */ |
| { |
| fi->framereg = FP_REGNUM; |
| } |
| else if ((insn & 0xff00) == 0xa300) /* addsp xx */ |
| { |
| sp_offset += 4 * (signed char) (insn & 0xff); |
| } |
| else if ((insn & 0xff0f) == 0x9b00 && /* ldi:20 xx,r0 */ |
| read_memory_unsigned_integer (current_pc + 4, 2) |
| == 0xac0f) /* sub r0,sp */ |
| { |
| /* large stack adjustment */ |
| sp_offset -= (((insn & 0xf0) << 12) | read_memory_unsigned_integer (current_pc + 2, 2)); |
| current_pc += 4; |
| } |
| else if (insn == 0x9f80 && /* ldi:32 xx,r0 */ |
| read_memory_unsigned_integer (current_pc + 6, 2) |
| == 0xac0f) /* sub r0,sp */ |
| { |
| /* large stack adjustment */ |
| sp_offset -= |
| (read_memory_unsigned_integer (current_pc + 2, 2) << 16 | |
| read_memory_unsigned_integer (current_pc + 4, 2)); |
| current_pc += 6; |
| } |
| } |
| |
| /* 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: init_extra_frame_info |
| Setup the frame's frame pointer, pc, and frame addresses for saved |
| registers. Most of the work is done in scan_prologue(). |
| |
| Note that when we are called for the last frame (currently active frame), |
| that fi->pc and fi->frame will already be setup. However, fi->frame will |
| be valid only if this routine uses FP. For previous frames, fi-frame will |
| always be correct (since that is derived from fr30_frame_chain ()). |
| |
| We can be called with the PC in the call dummy under two circumstances. |
| First, during normal backtracing, second, while figuring out the frame |
| pointer just prior to calling the target function (see run_stack_dummy). */ |
| |
| void |
| fr30_init_extra_frame_info (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 (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; |
| } |
| fr30_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) |
| 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 fr30_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: 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 |
| fr30_find_callers_reg (struct frame_info *fi, int regnum) |
| { |
| for (; fi; fi = fi->next) |
| 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_unsigned_integer (fi->fsr.regs[regnum], |
| REGISTER_RAW_SIZE (regnum)); |
| |
| return read_register (regnum); |
| } |
| |
| |
| /* Function: frame_chain |
| Figure out the frame prior to FI. Unfortunately, this involves |
| scanning the prologue of the caller, which will also be done |
| shortly by fr30_init_extra_frame_info. For the dummy frame, we |
| just return the stack pointer that was in use at the time the |
| function call was made. */ |
| |
| |
| CORE_ADDR |
| fr30_frame_chain (struct frame_info *fi) |
| { |
| CORE_ADDR fn_start, callers_pc, fp; |
| struct frame_info caller_fi; |
| int framereg; |
| |
| /* 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 = fr30_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 */ |
| |
| framereg = fi->framereg; |
| |
| /* If the caller is the startup code, we're at the end of the chain. */ |
| if (find_pc_partial_function (callers_pc, 0, &fn_start, 0)) |
| if (fn_start == entry_point_address ()) |
| return 0; |
| |
| memset (&caller_fi, 0, sizeof (caller_fi)); |
| caller_fi.pc = callers_pc; |
| fr30_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) |
| return fr30_find_callers_reg (fi, framereg); |
| else |
| return fi->frame + fi->framesize; |
| } |
| |
| /* 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. If the inner frame is a dummy frame, return its PC |
| instead of RP, because that's where "caller" of the dummy-frame |
| will be found. */ |
| |
| CORE_ADDR |
| fr30_frame_saved_pc (struct frame_info *fi) |
| { |
| if (PC_IN_CALL_DUMMY (fi->pc, fi->frame, fi->frame)) |
| return generic_read_register_dummy (fi->pc, fi->frame, PC_REGNUM); |
| else |
| return fr30_find_callers_reg (fi, RP_REGNUM); |
| } |
| |
| /* Function: fix_call_dummy |
| Pokes the callee function's address into the CALL_DUMMY assembly stub. |
| Assumes that the CALL_DUMMY looks like this: |
| jarl <offset24>, r31 |
| trap |
| */ |
| |
| int |
| fr30_fix_call_dummy (char *dummy, CORE_ADDR sp, CORE_ADDR fun, int nargs, |
| struct value **args, struct type *type, int gcc_p) |
| { |
| long offset24; |
| |
| offset24 = (long) fun - (long) entry_point_address (); |
| offset24 &= 0x3fffff; |
| offset24 |= 0xff800000; /* jarl <offset24>, r31 */ |
| |
| store_unsigned_integer ((unsigned int *) &dummy[2], 2, offset24 & 0xffff); |
| store_unsigned_integer ((unsigned int *) &dummy[0], 2, offset24 >> 16); |
| return 0; |
| } |