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Diffstat (limited to 'gdb/m88k-tdep.c')
| -rw-r--r-- | gdb/m88k-tdep.c | 629 |
1 files changed, 629 insertions, 0 deletions
diff --git a/gdb/m88k-tdep.c b/gdb/m88k-tdep.c new file mode 100644 index 0000000..f82cb76 --- /dev/null +++ b/gdb/m88k-tdep.c @@ -0,0 +1,629 @@ +/* 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 +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; +} |