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Diffstat (limited to 'gdb/i960-tdep.c')
| -rw-r--r-- | gdb/i960-tdep.c | 646 |
1 files changed, 646 insertions, 0 deletions
diff --git a/gdb/i960-tdep.c b/gdb/i960-tdep.c new file mode 100644 index 0000000..a82328a --- /dev/null +++ b/gdb/i960-tdep.c @@ -0,0 +1,646 @@ +/* Target-machine dependent code for the Intel 960 + Copyright (C) 1991 Free Software Foundation, Inc. + Contributed by Intel Corporation. + examine_prologue and other parts contributed by Wind River Systems. + +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 1, 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; see the file COPYING. If not, write to +the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */ + +/* Miscellaneous i80960-dependent routines. + Most are called from macros defined in "tm-i960.h". */ + +#include <stdio.h> +#include <signal.h> +#include "defs.h" +#include "param.h" +#include "symtab.h" +#include "value.h" +#include "frame.h" +#include "signame.h" +#include "ieee-float.h" + +/* Structure of i960 extended floating point format. */ + +const struct ext_format ext_format_i960 [] = { +/* tot sbyte smask expbyte manbyte */ + { 12, 9, 0x80, 9,8, 4,0 }, /* i960 */ +}; + +/* gdb960 is always running on a non-960 host. Check its characteristics. + This routine must be called as part of gdb initialization. */ + +static void +check_host() +{ + int i; + + static struct typestruct { + int hostsize; /* Size of type on host */ + int i960size; /* Size of type on i960 */ + char *typename; /* Name of type, for error msg */ + } types[] = { + { sizeof(short), 2, "short" }, + { sizeof(int), 4, "int" }, + { sizeof(long), 4, "long" }, + { sizeof(float), 4, "float" }, + { sizeof(double), 8, "double" }, + { sizeof(char *), 4, "pointer" }, + }; +#define TYPELEN (sizeof(types) / sizeof(struct typestruct)) + + /* Make sure that host type sizes are same as i960 + */ + for ( i = 0; i < TYPELEN; i++ ){ + if ( types[i].hostsize != types[i].i960size ){ + printf("sizeof(%s) != %d: PROCEED AT YOUR OWN RISK!\n", + types[i].typename, types[i].i960size ); + } + + } +} + +/* Examine an i960 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 gcc960 1.21, particularly + the routine i960_function_prologue (). A "regular expression" for + the function prologue is given below: + + (lda LRn, g14 + mov g14, g[0-7] + (mov 0, g14) | (lda 0, g14))? + + (mov[qtl]? g[0-15], r[4-15])* + ((addo [1-31], sp, sp) | (lda n(sp), sp))? + (st[qtl]? g[0-15], n(fp))* + + (cmpobne 0, g14, LFn + mov sp, g14 + lda 0x30(sp), sp + LFn: stq g0, (g14) + stq g4, 0x10(g14) + stq g8, 0x20(g14))? + + (st g14, n(fp))? + (mov g13,r[4-15])? +*/ + +/* Macros for extracting fields from i960 instructions. */ + +#define BITMASK(pos, width) (((0x1 << (width)) - 1) << (pos)) +#define EXTRACT_FIELD(val, pos, width) ((val) >> (pos) & BITMASK (0, width)) + +#define REG_SRC1(insn) EXTRACT_FIELD (insn, 0, 5) +#define REG_SRC2(insn) EXTRACT_FIELD (insn, 14, 5) +#define REG_SRCDST(insn) EXTRACT_FIELD (insn, 19, 5) +#define MEM_SRCDST(insn) EXTRACT_FIELD (insn, 19, 5) +#define MEMA_OFFSET(insn) EXTRACT_FIELD (insn, 0, 12) + +/* 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, and (for two-word instructions), *PWORD2 receives + the second. */ + +#define NEXT_PROLOGUE_INSN(addr, lim, pword1, pword2) \ + (((addr) < (lim)) ? next_insn (addr, pword1, pword2) : 0) + +static CORE_ADDR +examine_prologue (ip, limit, frame_addr, fsr) + register CORE_ADDR ip; + register CORE_ADDR limit; + FRAME_ADDR frame_addr; + struct frame_saved_regs *fsr; +{ + register CORE_ADDR next_ip; + register int src, dst; + register unsigned int *pcode; + unsigned int insn1, insn2; + int size; + int within_leaf_prologue; + CORE_ADDR save_addr; + static unsigned int varargs_prologue_code [] = + { + 0x3507a00c, /* cmpobne 0x0, g14, LFn */ + 0x5cf01601, /* mov sp, g14 */ + 0x8c086030, /* lda 0x30(sp), sp */ + 0xb2879000, /* LFn: stq g0, (g14) */ + 0xb2a7a010, /* stq g4, 0x10(g14) */ + 0xb2c7a020 /* stq g8, 0x20(g14) */ + }; + + /* Accept a leaf procedure prologue code fragment if present. + Note that ip might point to either the leaf or non-leaf + entry point; we look for the non-leaf entry point first: */ + + within_leaf_prologue = 0; + if ((next_ip = NEXT_PROLOGUE_INSN (ip, limit, &insn1, &insn2)) + && ((insn1 & 0xfffff000) == 0x8cf00000 /* lda LRx, g14 (MEMA) */ + || (insn1 & 0xfffffc60) == 0x8cf03000)) /* lda LRx, g14 (MEMB) */ + { + within_leaf_prologue = 1; + next_ip = NEXT_PROLOGUE_INSN (next_ip, limit, &insn1, &insn2); + } + + /* Now look for the prologue code at a leaf entry point: */ + + if (next_ip + && (insn1 & 0xff87ffff) == 0x5c80161e /* mov g14, gx */ + && REG_SRCDST (insn1) <= G0_REGNUM + 7) + { + within_leaf_prologue = 1; + if ((next_ip = NEXT_PROLOGUE_INSN (next_ip, limit, &insn1, &insn2)) + && (insn1 == 0x8cf00000 /* lda 0, g14 */ + || insn1 == 0x5cf01e00)) /* mov 0, g14 */ + { + ip = next_ip; + next_ip = NEXT_PROLOGUE_INSN (ip, limit, &insn1, &insn2); + within_leaf_prologue = 0; + } + } + + /* If something that looks like the beginning of a leaf prologue + has been seen, but the remainder of the prologue is missing, bail. + We don't know what we've got. */ + + if (within_leaf_prologue) + return (ip); + + /* Accept zero or more instances of "mov[qtl]? gx, ry", where y >= 4. + This may cause us to mistake the moving of a register + parameter to a local register for the saving of a callee-saved + register, but that can't be helped, since with the + "-fcall-saved" flag, any register can be made callee-saved. */ + + while (next_ip + && (insn1 & 0xfc802fb0) == 0x5c000610 + && (dst = REG_SRCDST (insn1)) >= (R0_REGNUM + 4)) + { + src = REG_SRC1 (insn1); + size = EXTRACT_FIELD (insn1, 24, 2) + 1; + save_addr = frame_addr + ((dst - R0_REGNUM) * 4); + while (size--) + { + fsr->regs[src++] = save_addr; + save_addr += 4; + } + ip = next_ip; + next_ip = NEXT_PROLOGUE_INSN (ip, limit, &insn1, &insn2); + } + + /* Accept an optional "addo n, sp, sp" or "lda n(sp), sp". */ + + if (next_ip && + ((insn1 & 0xffffffe0) == 0x59084800 /* addo n, sp, sp */ + || (insn1 & 0xfffff000) == 0x8c086000 /* lda n(sp), sp (MEMA) */ + || (insn1 & 0xfffffc60) == 0x8c087400)) /* lda n(sp), sp (MEMB) */ + { + ip = next_ip; + next_ip = NEXT_PROLOGUE_INSN (ip, limit, &insn1, &insn2); + } + + /* Accept zero or more instances of "st[qtl]? gx, n(fp)". + This may cause us to mistake the copying of a register + parameter to the frame for the saving of a callee-saved + register, but that can't be helped, since with the + "-fcall-saved" flag, any register can be made callee-saved. + We can, however, refuse to accept a save of register g14, + since that is matched explicitly below. */ + + while (next_ip && + ((insn1 & 0xf787f000) == 0x9287e000 /* stl? gx, n(fp) (MEMA) */ + || (insn1 & 0xf787fc60) == 0x9287f400 /* stl? gx, n(fp) (MEMB) */ + || (insn1 & 0xef87f000) == 0xa287e000 /* st[tq] gx, n(fp) (MEMA) */ + || (insn1 & 0xef87fc60) == 0xa287f400) /* st[tq] gx, n(fp) (MEMB) */ + && ((src = MEM_SRCDST (insn1)) != G14_REGNUM)) + { + save_addr = frame_addr + ((insn1 & BITMASK (12, 1)) + ? insn2 : MEMA_OFFSET (insn1)); + size = (insn1 & BITMASK (29, 1)) ? ((insn1 & BITMASK (28, 1)) ? 4 : 3) + : ((insn1 & BITMASK (27, 1)) ? 2 : 1); + while (size--) + { + fsr->regs[src++] = save_addr; + save_addr += 4; + } + ip = next_ip; + next_ip = NEXT_PROLOGUE_INSN (ip, limit, &insn1, &insn2); + } + + /* Accept the varargs prologue code if present. */ + + size = sizeof (varargs_prologue_code) / sizeof (int); + pcode = varargs_prologue_code; + while (size-- && next_ip && *pcode++ == insn1) + { + ip = next_ip; + next_ip = NEXT_PROLOGUE_INSN (ip, limit, &insn1, &insn2); + } + + /* Accept an optional "st g14, n(fp)". */ + + if (next_ip && + ((insn1 & 0xfffff000) == 0x92f7e000 /* st g14, n(fp) (MEMA) */ + || (insn1 & 0xfffffc60) == 0x92f7f400)) /* st g14, n(fp) (MEMB) */ + { + fsr->regs[G14_REGNUM] = frame_addr + ((insn1 & BITMASK (12, 1)) + ? insn2 : MEMA_OFFSET (insn1)); + ip = next_ip; + next_ip = NEXT_PROLOGUE_INSN (ip, limit, &insn1, &insn2); + } + + /* Accept zero or one instance of "mov g13, ry", where y >= 4. + This is saving the address where a struct should be returned. */ + + if (next_ip + && (insn1 & 0xff802fbf) == 0x5c00061d + && (dst = REG_SRCDST (insn1)) >= (R0_REGNUM + 4)) + { + save_addr = frame_addr + ((dst - R0_REGNUM) * 4); + fsr->regs[G0_REGNUM+13] = save_addr; + ip = next_ip; +#if 0 /* We'll need this once there is a subsequent instruction examined. */ + next_ip = NEXT_PROLOGUE_INSN (ip, limit, &insn1, &insn2); +#endif + } + + 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, (FRAME_ADDR) 0, &saved_regs_dummy)); +} + +/* 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_cache_obstack, since + it is fairly expensive. */ + +void +frame_find_saved_regs (fi, fsr) + struct frame_info *fi; + struct frame_saved_regs *fsr; +{ + register CORE_ADDR next_addr; + register CORE_ADDR *saved_regs; + register int regnum; + register struct frame_saved_regs *cache_fsr; + extern struct obstack frame_cache_obstack; + CORE_ADDR ip; + struct symtab_and_line sal; + CORE_ADDR limit; + + if (!fi->fsr) + { + cache_fsr = (struct frame_saved_regs *) + obstack_alloc (&frame_cache_obstack, + sizeof (struct frame_saved_regs)); + bzero (cache_fsr, 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. */ + + ip = get_pc_function_start (fi->pc); + sal = find_pc_line (ip, 0); + limit = (sal.end && sal.end < fi->pc) ? sal.end: fi->pc; + + examine_prologue (ip, limit, fi->frame, cache_fsr); + + /* Record the addresses at which the local registers are saved. + Strictly speaking, we should only do this for non-leaf procedures, + but no one will ever look at these values if it is a leaf procedure, + since local registers are always caller-saved. */ + + next_addr = (CORE_ADDR) fi->frame; + saved_regs = cache_fsr->regs; + for (regnum = R0_REGNUM; regnum <= R15_REGNUM; regnum++) + { + *saved_regs++ = next_addr; + next_addr += 4; + } + + cache_fsr->regs[FP_REGNUM] = cache_fsr->regs[PFP_REGNUM]; + } + + *fsr = *fi->fsr; + + /* Fetch the value of the sp from memory every time, since it + is conceivable that it has changed since the cache was flushed. + This unfortunately undoes much of the savings from caching the + saved register values. I suggest adding an argument to + get_frame_saved_regs () specifying the register number we're + interested in (or -1 for all registers). This would be passed + through to FRAME_FIND_SAVED_REGS (), permitting more efficient + computation of saved register addresses (e.g., on the i960, + we don't have to examine the prologue to find local registers). + -- markf@wrs.com + FIXME, we don't need to refetch this, since the cache is cleared + every time the child process is restarted. If GDB itself + modifies SP, it has to clear the cache by hand (does it?). -gnu */ + + fsr->regs[SP_REGNUM] = read_memory_integer (fsr->regs[SP_REGNUM], 4); +} + +/* 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, must_be_correct) + struct frame_info *fi; +{ + register FRAME frame; + struct frame_saved_regs fsr; + CORE_ADDR ap; + + /* If g14 was saved in the frame by the function prologue code, return + the saved value. If the frame is current and we are being sloppy, + return the value of g14. Otherwise, return zero. */ + + frame = FRAME_INFO_ID (fi); + get_frame_saved_regs (fi, &fsr); + if (fsr.regs[G14_REGNUM]) + ap = read_memory_integer (fsr.regs[G14_REGNUM],4); + else { + if (must_be_correct) + return 0; /* Don't cache this result */ + if (get_next_frame (frame)) + ap = 0; + else + ap = read_register (G14_REGNUM); + } + fi->arg_pointer = ap; /* Cache it for next time */ + return ap; +} + +/* Return the address of the return struct for the frame + described by FI. Returns 0 if the address is unknown. */ + +CORE_ADDR +frame_struct_result_address (fi) + struct frame_info *fi; +{ + register FRAME frame; + struct frame_saved_regs fsr; + CORE_ADDR ap; + + /* If the frame is non-current, check to see if g14 was saved in the + frame by the function prologue code; return the saved value if so, + zero otherwise. If the frame is current, return the value of g14. + + FIXME, shouldn't this use the saved value as long as we are past + the function prologue, and only use the current value if we have + no saved value and are at TOS? -- gnu@cygnus.com */ + + frame = FRAME_INFO_ID (fi); + if (get_next_frame (frame)) { + get_frame_saved_regs (fi, &fsr); + if (fsr.regs[G13_REGNUM]) + ap = read_memory_integer (fsr.regs[G13_REGNUM],4); + else + ap = 0; + } else { + ap = read_register (G13_REGNUM); + } + return ap; +} + +/* Return address to which the currently executing leafproc will return, + or 0 if ip is not in a leafproc (or if we can't tell if it is). + + Do this by finding the starting address of the routine in which ip lies. + If the instruction there is "mov g14, gx" (where x is in [0,7]), this + is a leafproc and the return address is in register gx. Well, this is + true unless the return address points at a RET instruction in the current + procedure, which indicates that we have a 'dual entry' routine that + has been entered through the CALL entry point. */ + +CORE_ADDR +leafproc_return (ip) + CORE_ADDR ip; /* ip from currently executing function */ +{ + int i; + register struct misc_function *mf; + char *p; + int dst; + unsigned int insn1, insn2; + CORE_ADDR return_addr; + char *index (); + + if ((i = find_pc_misc_function (ip)) >= 0) + { + mf = &misc_function_vector[i]; + if ((p = index (mf->name, '.')) && !strcmp (p, ".lf")) + { + if (next_insn (mf->address, &insn1, &insn2) + && (insn1 & 0xff87ffff) == 0x5c80161e /* mov g14, gx */ + && (dst = REG_SRCDST (insn1)) <= G0_REGNUM + 7) + { + /* Get the return address. If the "mov g14, gx" + instruction hasn't been executed yet, read + the return address from g14; otherwise, read it + from the register into which g14 was moved. */ + + return_addr = read_register ((ip == mf->address) + ? G14_REGNUM : dst); + + /* We know we are in a leaf procedure, but we don't know + whether the caller actually did a "bal" to the ".lf" + entry point, or a normal "call" to the non-leaf entry + point one instruction before. In the latter case, the + return address will be the address of a "ret" + instruction within the procedure itself. We test for + this below. */ + + if (!next_insn (return_addr, &insn1, &insn2) + || (insn1 & 0xff000000) != 0xa000000 /* ret */ + || find_pc_misc_function (return_addr) != i) + return (return_addr); + } + } + } + + return (0); +} + +/* Immediately after a function call, return the saved pc. + Can't go through the frames for this because on some machines + the new frame is not set up until the new function executes + some instructions. + On the i960, the frame *is* set up immediately after the call, + unless the function is a leaf procedure. */ + +CORE_ADDR +saved_pc_after_call (frame) + FRAME frame; +{ + CORE_ADDR saved_pc; + CORE_ADDR get_frame_pc (); + + saved_pc = leafproc_return (get_frame_pc (frame)); + if (!saved_pc) + saved_pc = FRAME_SAVED_PC (frame); + + return (saved_pc); +} + +/* Discard from the stack the innermost frame, + restoring all saved registers. */ + +pop_frame () +{ + register struct frame_info *current_fi, *prev_fi; + register int i; + CORE_ADDR save_addr; + CORE_ADDR leaf_return_addr; + struct frame_saved_regs fsr; + char local_regs_buf[16 * 4]; + + current_fi = get_frame_info (get_current_frame ()); + + /* First, undo what the hardware does when we return. + If this is a non-leaf procedure, restore local registers from + the save area in the calling frame. Otherwise, load the return + address obtained from leafproc_return () into the rip. */ + + leaf_return_addr = leafproc_return (current_fi->pc); + if (!leaf_return_addr) + { + /* Non-leaf procedure. Restore local registers, incl IP. */ + prev_fi = get_frame_info (get_prev_frame (FRAME_INFO_ID (current_fi))); + read_memory (prev_fi->frame, local_regs_buf, sizeof (local_regs_buf)); + write_register_bytes (REGISTER_BYTE (R0_REGNUM), local_regs_buf, + sizeof (local_regs_buf)); + + /* Restore frame pointer. */ + write_register (FP_REGNUM, prev_fi->frame); + } + else + { + /* Leaf procedure. Just restore the return address into the IP. */ + write_register (RIP_REGNUM, leaf_return_addr); + } + + /* Now restore any global regs that the current function had saved. */ + get_frame_saved_regs (current_fi, &fsr); + for (i = G0_REGNUM; i < G14_REGNUM; i++) + { + if (save_addr = fsr.regs[i]) + write_register (i, read_memory_integer (save_addr, 4)); + } + + /* Flush the frame cache, create a frame for the new innermost frame, + and make it the current frame. */ + + flush_cached_frames (); + set_current_frame (create_new_frame (read_register (FP_REGNUM), read_pc ())); +} + +/* Print out text describing a "signal number" with which the i80960 halted. + + See the file "fault.c" in the nindy monitor source code for a list + of stop codes. */ + +void +print_fault( siggnal ) + int siggnal; /* Signal number, as returned by target_wait() */ +{ + static char unknown[] = "Unknown fault or trace"; + static char *sigmsgs[] = { + /* FAULTS */ + "parallel fault", /* 0x00 */ + unknown, /* 0x01 */ + "operation fault", /* 0x02 */ + "arithmetic fault", /* 0x03 */ + "floating point fault", /* 0x04 */ + "constraint fault", /* 0x05 */ + "virtual memory fault", /* 0x06 */ + "protection fault", /* 0x07 */ + "machine fault", /* 0x08 */ + "structural fault", /* 0x09 */ + "type fault", /* 0x0a */ + "reserved (0xb) fault", /* 0x0b */ + "process fault", /* 0x0c */ + "descriptor fault", /* 0x0d */ + "event fault", /* 0x0e */ + "reserved (0xf) fault", /* 0x0f */ + + /* TRACES */ + "single-step trace", /* 0x10 */ + "branch trace", /* 0x11 */ + "call trace", /* 0x12 */ + "return trace", /* 0x13 */ + "pre-return trace", /* 0x14 */ + "supervisor call trace",/* 0x15 */ + "breakpoint trace", /* 0x16 */ + }; +# define NUMMSGS ((int)( sizeof(sigmsgs) / sizeof(sigmsgs[0]) )) + + if (siggnal < NSIG) { + printf ("\nProgram received signal %d, %s\n", + siggnal, + sys_siglist[siggnal]); + } else { + /* The various target_wait()s bias the 80960 "signal number" + by adding NSIG to it, so it won't get confused with any + of the Unix signals elsewhere in GDB. We need to + "unbias" it before using it. */ + siggnal -= NSIG; + + printf("Program stopped for reason #%d: %s.\n", siggnal, + (siggnal < NUMMSGS && siggnal >= 0)? + sigmsgs[siggnal] : unknown ); + } +} + +/* Initialization stub */ + +_initialize_i960_tdep () +{ + check_host (); +} |