| /* Target-machine dependent code for Motorola 88000 series, for GDB. |
| Copyright 1988, 1990, 1991, 1994, 1995 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 "value.h" |
| #include "gdbcore.h" |
| #include "symtab.h" |
| #include "setjmp.h" |
| #include "value.h" |
| |
| /* Size of an instruction */ |
| #define BYTES_PER_88K_INSN 4 |
| |
| void frame_find_saved_regs (); |
| |
| /* Is this target an m88110? Otherwise assume m88100. This has |
| relevance for the ways in which we screw with instruction pointers. */ |
| |
| int target_is_m88110 = 0; |
| |
| /* The m88k kernel aligns all instructions on 4-byte boundaries. The |
| kernel also uses the least significant two bits for its own hocus |
| pocus. When gdb receives an address from the kernel, it needs to |
| preserve those right-most two bits, but gdb also needs to be careful |
| to realize that those two bits are not really a part of the address |
| of an instruction. Shrug. */ |
| |
| CORE_ADDR |
| m88k_addr_bits_remove (addr) |
| CORE_ADDR addr; |
| { |
| return ((addr) & ~3); |
| } |
| |
| |
| /* 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 us, the frame address is its stack pointer value, so we look up |
| the function prologue to determine the caller's sp value, and return it. */ |
| |
| CORE_ADDR |
| frame_chain (thisframe) |
| struct frame_info *thisframe; |
| { |
| |
| frame_find_saved_regs (thisframe, (struct frame_saved_regs *) 0); |
| /* NOTE: this depends on frame_find_saved_regs returning the VALUE, not |
| the ADDRESS, of SP_REGNUM. It also depends on the cache of |
| frame_find_saved_regs results. */ |
| if (thisframe->fsr->regs[SP_REGNUM]) |
| return thisframe->fsr->regs[SP_REGNUM]; |
| else |
| return thisframe->frame; /* Leaf fn -- next frame up has same SP. */ |
| } |
| |
| int |
| frameless_function_invocation (frame) |
| struct frame_info *frame; |
| { |
| |
| frame_find_saved_regs (frame, (struct frame_saved_regs *) 0); |
| /* NOTE: this depends on frame_find_saved_regs returning the VALUE, not |
| the ADDRESS, of SP_REGNUM. It also depends on the cache of |
| frame_find_saved_regs results. */ |
| if (frame->fsr->regs[SP_REGNUM]) |
| return 0; /* Frameful -- return addr saved somewhere */ |
| else |
| return 1; /* Frameless -- no saved return address */ |
| } |
| |
| void |
| init_extra_frame_info (fromleaf, frame) |
| int fromleaf; |
| struct frame_info *frame; |
| { |
| frame->fsr = 0; /* Not yet allocated */ |
| frame->args_pointer = 0; /* Unknown */ |
| frame->locals_pointer = 0; /* Unknown */ |
| } |
| |
| /* Examine an m88k function prologue, recording the addresses at which |
| registers are saved explicitly by the prologue code, and returning |
| the address of the first instruction after the prologue (but not |
| after the instruction at address LIMIT, as explained below). |
| |
| LIMIT places an upper bound on addresses of the instructions to be |
| examined. If the prologue code scan reaches LIMIT, the scan is |
| aborted and LIMIT is returned. This is used, when examining the |
| prologue for the current frame, to keep examine_prologue () from |
| claiming that a given register has been saved when in fact the |
| instruction that saves it has not yet been executed. LIMIT is used |
| at other times to stop the scan when we hit code after the true |
| function prologue (e.g. for the first source line) which might |
| otherwise be mistaken for function prologue. |
| |
| The format of the function prologue matched by this routine is |
| derived from examination of the source to gcc 1.95, particularly |
| the routine output_prologue () in config/out-m88k.c. |
| |
| subu r31,r31,n # stack pointer update |
| |
| (st rn,r31,offset)? # save incoming regs |
| (st.d rn,r31,offset)? |
| |
| (addu r30,r31,n)? # frame pointer update |
| |
| (pic sequence)? # PIC code prologue |
| |
| (or rn,rm,0)? # Move parameters to other regs |
| */ |
| |
| /* Macros for extracting fields from instructions. */ |
| |
| #define BITMASK(pos, width) (((0x1 << (width)) - 1) << (pos)) |
| #define EXTRACT_FIELD(val, pos, width) ((val) >> (pos) & BITMASK (0, width)) |
| #define SUBU_OFFSET(x) ((unsigned)(x & 0xFFFF)) |
| #define ST_OFFSET(x) ((unsigned)((x) & 0xFFFF)) |
| #define ST_SRC(x) EXTRACT_FIELD ((x), 21, 5) |
| #define ADDU_OFFSET(x) ((unsigned)(x & 0xFFFF)) |
| |
| /* |
| * prologue_insn_tbl is a table of instructions which may comprise a |
| * function prologue. Associated with each table entry (corresponding |
| * to a single instruction or group of instructions), is an action. |
| * This action is used by examine_prologue (below) to determine |
| * the state of certain machine registers and where the stack frame lives. |
| */ |
| |
| enum prologue_insn_action |
| { |
| PIA_SKIP, /* don't care what the instruction does */ |
| PIA_NOTE_ST, /* note register stored and where */ |
| PIA_NOTE_STD, /* note pair of registers stored and where */ |
| PIA_NOTE_SP_ADJUSTMENT, /* note stack pointer adjustment */ |
| PIA_NOTE_FP_ASSIGNMENT, /* note frame pointer assignment */ |
| PIA_NOTE_PROLOGUE_END, /* no more prologue */ |
| }; |
| |
| struct prologue_insns |
| { |
| unsigned long insn; |
| unsigned long mask; |
| enum prologue_insn_action action; |
| }; |
| |
| struct prologue_insns prologue_insn_tbl[] = |
| { |
| /* Various register move instructions */ |
| {0x58000000, 0xf800ffff, PIA_SKIP}, /* or/or.u with immed of 0 */ |
| {0xf4005800, 0xfc1fffe0, PIA_SKIP}, /* or rd, r0, rs */ |
| {0xf4005800, 0xfc00ffff, PIA_SKIP}, /* or rd, rs, r0 */ |
| |
| /* Stack pointer setup: "subu sp, sp, n" where n is a multiple of 8 */ |
| {0x67ff0000, 0xffff0007, PIA_NOTE_SP_ADJUSTMENT}, |
| |
| /* Frame pointer assignment: "addu r30, r31, n" */ |
| {0x63df0000, 0xffff0000, PIA_NOTE_FP_ASSIGNMENT}, |
| |
| /* Store to stack instructions; either "st rx, sp, n" or "st.d rx, sp, n" */ |
| {0x241f0000, 0xfc1f0000, PIA_NOTE_ST}, /* st rx, sp, n */ |
| {0x201f0000, 0xfc1f0000, PIA_NOTE_STD}, /* st.d rs, sp, n */ |
| |
| /* Instructions needed for setting up r25 for pic code. */ |
| {0x5f200000, 0xffff0000, PIA_SKIP}, /* or.u r25, r0, offset_high */ |
| {0xcc000002, 0xffffffff, PIA_SKIP}, /* bsr.n Lab */ |
| {0x5b390000, 0xffff0000, PIA_SKIP}, /* or r25, r25, offset_low */ |
| {0xf7396001, 0xffffffff, PIA_SKIP}, /* Lab: addu r25, r25, r1 */ |
| |
| /* Various branch or jump instructions which have a delay slot -- these |
| do not form part of the prologue, but the instruction in the delay |
| slot might be a store instruction which should be noted. */ |
| {0xc4000000, 0xe4000000, PIA_NOTE_PROLOGUE_END}, |
| /* br.n, bsr.n, bb0.n, or bb1.n */ |
| {0xec000000, 0xfc000000, PIA_NOTE_PROLOGUE_END}, /* bcnd.n */ |
| {0xf400c400, 0xfffff7e0, PIA_NOTE_PROLOGUE_END} /* jmp.n or jsr.n */ |
| |
| }; |
| |
| |
| /* Fetch the instruction at ADDR, returning 0 if ADDR is beyond LIM or |
| is not the address of a valid instruction, the address of the next |
| instruction beyond ADDR otherwise. *PWORD1 receives the first word |
| of the instruction. */ |
| |
| #define NEXT_PROLOGUE_INSN(addr, lim, pword1) \ |
| (((addr) < (lim)) ? next_insn (addr, pword1) : 0) |
| |
| /* Read the m88k instruction at 'memaddr' and return the address of |
| the next instruction after that, or 0 if 'memaddr' is not the |
| address of a valid instruction. The instruction |
| is stored at 'pword1'. */ |
| |
| CORE_ADDR |
| next_insn (memaddr, pword1) |
| unsigned long *pword1; |
| CORE_ADDR memaddr; |
| { |
| *pword1 = read_memory_integer (memaddr, BYTES_PER_88K_INSN); |
| return memaddr + BYTES_PER_88K_INSN; |
| } |
| |
| /* Read a register from frames called by us (or from the hardware regs). */ |
| |
| static int |
| read_next_frame_reg (frame, regno) |
| struct frame_info *frame; |
| int regno; |
| { |
| for (; frame; frame = frame->next) |
| { |
| if (regno == SP_REGNUM) |
| return FRAME_FP (frame); |
| else if (frame->fsr->regs[regno]) |
| return read_memory_integer (frame->fsr->regs[regno], 4); |
| } |
| return read_register (regno); |
| } |
| |
| /* Examine the prologue of a function. `ip' points to the first instruction. |
| `limit' is the limit of the prologue (e.g. the addr of the first |
| linenumber, or perhaps the program counter if we're stepping through). |
| `frame_sp' is the stack pointer value in use in this frame. |
| `fsr' is a pointer to a frame_saved_regs structure into which we put |
| info about the registers saved by this frame. |
| `fi' is a struct frame_info pointer; we fill in various fields in it |
| to reflect the offsets of the arg pointer and the locals pointer. */ |
| |
| static CORE_ADDR |
| examine_prologue (ip, limit, frame_sp, fsr, fi) |
| register CORE_ADDR ip; |
| register CORE_ADDR limit; |
| CORE_ADDR frame_sp; |
| struct frame_saved_regs *fsr; |
| struct frame_info *fi; |
| { |
| register CORE_ADDR next_ip; |
| register int src; |
| unsigned int insn; |
| int size, offset; |
| char must_adjust[32]; /* If set, must adjust offsets in fsr */ |
| int sp_offset = -1; /* -1 means not set (valid must be mult of 8) */ |
| int fp_offset = -1; /* -1 means not set */ |
| CORE_ADDR frame_fp; |
| CORE_ADDR prologue_end = 0; |
| |
| memset (must_adjust, '\0', sizeof (must_adjust)); |
| next_ip = NEXT_PROLOGUE_INSN (ip, limit, &insn); |
| |
| while (next_ip) |
| { |
| struct prologue_insns *pip; |
| |
| for (pip = prologue_insn_tbl; (insn & pip->mask) != pip->insn;) |
| if (++pip >= prologue_insn_tbl + sizeof prologue_insn_tbl) |
| goto end_of_prologue_found; /* not a prologue insn */ |
| |
| switch (pip->action) |
| { |
| case PIA_NOTE_ST: |
| case PIA_NOTE_STD: |
| if (sp_offset != -1) |
| { |
| src = ST_SRC (insn); |
| offset = ST_OFFSET (insn); |
| must_adjust[src] = 1; |
| fsr->regs[src++] = offset; /* Will be adjusted later */ |
| if (pip->action == PIA_NOTE_STD && src < 32) |
| { |
| offset += 4; |
| must_adjust[src] = 1; |
| fsr->regs[src++] = offset; |
| } |
| } |
| else |
| goto end_of_prologue_found; |
| break; |
| case PIA_NOTE_SP_ADJUSTMENT: |
| if (sp_offset == -1) |
| sp_offset = -SUBU_OFFSET (insn); |
| else |
| goto end_of_prologue_found; |
| break; |
| case PIA_NOTE_FP_ASSIGNMENT: |
| if (fp_offset == -1) |
| fp_offset = ADDU_OFFSET (insn); |
| else |
| goto end_of_prologue_found; |
| break; |
| case PIA_NOTE_PROLOGUE_END: |
| if (!prologue_end) |
| prologue_end = ip; |
| break; |
| case PIA_SKIP: |
| default: |
| /* Do nothing */ |
| break; |
| } |
| |
| ip = next_ip; |
| next_ip = NEXT_PROLOGUE_INSN (ip, limit, &insn); |
| } |
| |
| end_of_prologue_found: |
| |
| if (prologue_end) |
| ip = prologue_end; |
| |
| /* We're done with the prologue. If we don't care about the stack |
| frame itself, just return. (Note that fsr->regs has been trashed, |
| but the one caller who calls with fi==0 passes a dummy there.) */ |
| |
| if (fi == 0) |
| return ip; |
| |
| /* |
| OK, now we have: |
| |
| sp_offset original (before any alloca calls) displacement of SP |
| (will be negative). |
| |
| fp_offset displacement from original SP to the FP for this frame |
| or -1. |
| |
| fsr->regs[0..31] displacement from original SP to the stack |
| location where reg[0..31] is stored. |
| |
| must_adjust[0..31] set if corresponding offset was set. |
| |
| If alloca has been called between the function prologue and the current |
| IP, then the current SP (frame_sp) will not be the original SP as set by |
| the function prologue. If the current SP is not the original SP, then the |
| compiler will have allocated an FP for this frame, fp_offset will be set, |
| and we can use it to calculate the original SP. |
| |
| Then, we figure out where the arguments and locals are, and relocate the |
| offsets in fsr->regs to absolute addresses. */ |
| |
| if (fp_offset != -1) |
| { |
| /* We have a frame pointer, so get it, and base our calc's on it. */ |
| frame_fp = (CORE_ADDR) read_next_frame_reg (fi->next, ACTUAL_FP_REGNUM); |
| frame_sp = frame_fp - fp_offset; |
| } |
| else |
| { |
| /* We have no frame pointer, therefore frame_sp is still the same value |
| as set by prologue. But where is the frame itself? */ |
| if (must_adjust[SRP_REGNUM]) |
| { |
| /* Function header saved SRP (r1), the return address. Frame starts |
| 4 bytes down from where it was saved. */ |
| frame_fp = frame_sp + fsr->regs[SRP_REGNUM] - 4; |
| fi->locals_pointer = frame_fp; |
| } |
| else |
| { |
| /* Function header didn't save SRP (r1), so we are in a leaf fn or |
| are otherwise confused. */ |
| frame_fp = -1; |
| } |
| } |
| |
| /* The locals are relative to the FP (whether it exists as an allocated |
| register, or just as an assumed offset from the SP) */ |
| fi->locals_pointer = frame_fp; |
| |
| /* The arguments are just above the SP as it was before we adjusted it |
| on entry. */ |
| fi->args_pointer = frame_sp - sp_offset; |
| |
| /* Now that we know the SP value used by the prologue, we know where |
| it saved all the registers. */ |
| for (src = 0; src < 32; src++) |
| if (must_adjust[src]) |
| fsr->regs[src] += frame_sp; |
| |
| /* The saved value of the SP is always known. */ |
| /* (we hope...) */ |
| if (fsr->regs[SP_REGNUM] != 0 |
| && fsr->regs[SP_REGNUM] != frame_sp - sp_offset) |
| fprintf_unfiltered (gdb_stderr, "Bad saved SP value %x != %x, offset %x!\n", |
| fsr->regs[SP_REGNUM], |
| frame_sp - sp_offset, sp_offset); |
| |
| fsr->regs[SP_REGNUM] = frame_sp - sp_offset; |
| |
| return (ip); |
| } |
| |
| /* Given an ip value corresponding to the start of a function, |
| return the ip of the first instruction after the function |
| prologue. */ |
| |
| CORE_ADDR |
| m88k_skip_prologue (ip) |
| CORE_ADDR (ip); |
| { |
| struct frame_saved_regs saved_regs_dummy; |
| struct symtab_and_line sal; |
| CORE_ADDR limit; |
| |
| sal = find_pc_line (ip, 0); |
| limit = (sal.end) ? sal.end : 0xffffffff; |
| |
| return (examine_prologue (ip, limit, (CORE_ADDR) 0, &saved_regs_dummy, |
| (struct frame_info *) 0)); |
| } |
| |
| /* Put here the code to store, into a struct frame_saved_regs, |
| the addresses of the saved registers of frame described by FRAME_INFO. |
| This includes special registers such as pc and fp saved in special |
| ways in the stack frame. sp is even more special: |
| the address we return for it IS the sp for the next frame. |
| |
| We cache the result of doing this in the frame_obstack, since it is |
| fairly expensive. */ |
| |
| void |
| frame_find_saved_regs (fi, fsr) |
| struct frame_info *fi; |
| struct frame_saved_regs *fsr; |
| { |
| register struct frame_saved_regs *cache_fsr; |
| CORE_ADDR ip; |
| struct symtab_and_line sal; |
| CORE_ADDR limit; |
| |
| if (!fi->fsr) |
| { |
| cache_fsr = (struct frame_saved_regs *) |
| frame_obstack_alloc (sizeof (struct frame_saved_regs)); |
| memset (cache_fsr, '\0', sizeof (struct frame_saved_regs)); |
| fi->fsr = cache_fsr; |
| |
| /* Find the start and end of the function prologue. If the PC |
| is in the function prologue, we only consider the part that |
| has executed already. In the case where the PC is not in |
| the function prologue, we set limit to two instructions beyond |
| where the prologue ends in case if any of the prologue instructions |
| were moved into a delay slot of a branch instruction. */ |
| |
| ip = get_pc_function_start (fi->pc); |
| sal = find_pc_line (ip, 0); |
| limit = (sal.end && sal.end < fi->pc) ? sal.end + 2 * BYTES_PER_88K_INSN |
| : fi->pc; |
| |
| /* This will fill in fields in *fi as well as in cache_fsr. */ |
| #ifdef SIGTRAMP_FRAME_FIXUP |
| if (fi->signal_handler_caller) |
| SIGTRAMP_FRAME_FIXUP (fi->frame); |
| #endif |
| examine_prologue (ip, limit, fi->frame, cache_fsr, fi); |
| #ifdef SIGTRAMP_SP_FIXUP |
| if (fi->signal_handler_caller && fi->fsr->regs[SP_REGNUM]) |
| SIGTRAMP_SP_FIXUP (fi->fsr->regs[SP_REGNUM]); |
| #endif |
| } |
| |
| if (fsr) |
| *fsr = *fi->fsr; |
| } |
| |
| /* Return the address of the locals block for the frame |
| described by FI. Returns 0 if the address is unknown. |
| NOTE! Frame locals are referred to by negative offsets from the |
| argument pointer, so this is the same as frame_args_address(). */ |
| |
| CORE_ADDR |
| frame_locals_address (fi) |
| struct frame_info *fi; |
| { |
| struct frame_saved_regs fsr; |
| |
| if (fi->args_pointer) /* Cached value is likely there. */ |
| return fi->args_pointer; |
| |
| /* Nope, generate it. */ |
| |
| get_frame_saved_regs (fi, &fsr); |
| |
| return fi->args_pointer; |
| } |
| |
| /* Return the address of the argument block for the frame |
| described by FI. Returns 0 if the address is unknown. */ |
| |
| CORE_ADDR |
| frame_args_address (fi) |
| struct frame_info *fi; |
| { |
| struct frame_saved_regs fsr; |
| |
| if (fi->args_pointer) /* Cached value is likely there. */ |
| return fi->args_pointer; |
| |
| /* Nope, generate it. */ |
| |
| get_frame_saved_regs (fi, &fsr); |
| |
| return fi->args_pointer; |
| } |
| |
| /* Return the saved PC from this frame. |
| |
| If the frame has a memory copy of SRP_REGNUM, use that. If not, |
| just use the register SRP_REGNUM itself. */ |
| |
| CORE_ADDR |
| frame_saved_pc (frame) |
| struct frame_info *frame; |
| { |
| return read_next_frame_reg (frame, SRP_REGNUM); |
| } |
| |
| |
| #define DUMMY_FRAME_SIZE 192 |
| |
| static void |
| write_word (sp, word) |
| CORE_ADDR sp; |
| ULONGEST word; |
| { |
| register int len = REGISTER_SIZE; |
| char buffer[MAX_REGISTER_RAW_SIZE]; |
| |
| store_unsigned_integer (buffer, len, word); |
| write_memory (sp, buffer, len); |
| } |
| |
| void |
| m88k_push_dummy_frame () |
| { |
| register CORE_ADDR sp = read_register (SP_REGNUM); |
| register int rn; |
| int offset; |
| |
| sp -= DUMMY_FRAME_SIZE; /* allocate a bunch of space */ |
| |
| for (rn = 0, offset = 0; rn <= SP_REGNUM; rn++, offset += 4) |
| write_word (sp + offset, read_register (rn)); |
| |
| write_word (sp + offset, read_register (SXIP_REGNUM)); |
| offset += 4; |
| |
| write_word (sp + offset, read_register (SNIP_REGNUM)); |
| offset += 4; |
| |
| write_word (sp + offset, read_register (SFIP_REGNUM)); |
| offset += 4; |
| |
| write_word (sp + offset, read_register (PSR_REGNUM)); |
| offset += 4; |
| |
| write_word (sp + offset, read_register (FPSR_REGNUM)); |
| offset += 4; |
| |
| write_word (sp + offset, read_register (FPCR_REGNUM)); |
| offset += 4; |
| |
| write_register (SP_REGNUM, sp); |
| write_register (ACTUAL_FP_REGNUM, sp); |
| } |
| |
| void |
| pop_frame () |
| { |
| register struct frame_info *frame = get_current_frame (); |
| register CORE_ADDR fp; |
| register int regnum; |
| struct frame_saved_regs fsr; |
| |
| fp = FRAME_FP (frame); |
| get_frame_saved_regs (frame, &fsr); |
| |
| if (PC_IN_CALL_DUMMY (read_pc (), read_register (SP_REGNUM), FRAME_FP (fi))) |
| { |
| /* FIXME: I think get_frame_saved_regs should be handling this so |
| that we can deal with the saved registers properly (e.g. frame |
| 1 is a call dummy, the user types "frame 2" and then "print $ps"). */ |
| register CORE_ADDR sp = read_register (ACTUAL_FP_REGNUM); |
| int offset; |
| |
| for (regnum = 0, offset = 0; regnum <= SP_REGNUM; regnum++, offset += 4) |
| (void) write_register (regnum, read_memory_integer (sp + offset, 4)); |
| |
| write_register (SXIP_REGNUM, read_memory_integer (sp + offset, 4)); |
| offset += 4; |
| |
| write_register (SNIP_REGNUM, read_memory_integer (sp + offset, 4)); |
| offset += 4; |
| |
| write_register (SFIP_REGNUM, read_memory_integer (sp + offset, 4)); |
| offset += 4; |
| |
| write_register (PSR_REGNUM, read_memory_integer (sp + offset, 4)); |
| offset += 4; |
| |
| write_register (FPSR_REGNUM, read_memory_integer (sp + offset, 4)); |
| offset += 4; |
| |
| write_register (FPCR_REGNUM, read_memory_integer (sp + offset, 4)); |
| offset += 4; |
| |
| } |
| else |
| { |
| for (regnum = FP_REGNUM; regnum > 0; regnum--) |
| if (fsr.regs[regnum]) |
| write_register (regnum, |
| read_memory_integer (fsr.regs[regnum], 4)); |
| write_pc (frame_saved_pc (frame)); |
| } |
| reinit_frame_cache (); |
| } |
| |
| void |
| _initialize_m88k_tdep () |
| { |
| tm_print_insn = print_insn_m88k; |
| } |