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author | Stan Shebs <shebs@codesourcery.com> | 1999-04-16 01:34:07 +0000 |
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committer | Stan Shebs <shebs@codesourcery.com> | 1999-04-16 01:34:07 +0000 |
commit | 071ea11e85eb9d529cc5eb3d35f6247466a21b99 (patch) | |
tree | 5deda65b8d7b04d1f4cbc534c3206d328e1267ec /gdb/m32r-stub.c | |
parent | 1730ec6b1848f0f32154277f788fb29f88d8475b (diff) | |
download | ppe42-binutils-071ea11e85eb9d529cc5eb3d35f6247466a21b99.tar.gz ppe42-binutils-071ea11e85eb9d529cc5eb3d35f6247466a21b99.zip |
Initial creation of sourceware repository
Diffstat (limited to 'gdb/m32r-stub.c')
-rw-r--r-- | gdb/m32r-stub.c | 1621 |
1 files changed, 0 insertions, 1621 deletions
diff --git a/gdb/m32r-stub.c b/gdb/m32r-stub.c deleted file mode 100644 index 1fed041b28..0000000000 --- a/gdb/m32r-stub.c +++ /dev/null @@ -1,1621 +0,0 @@ -/**************************************************************************** - - THIS SOFTWARE IS NOT COPYRIGHTED - - HP offers the following for use in the public domain. HP makes no - warranty with regard to the software or it's performance and the - user accepts the software "AS IS" with all faults. - - HP DISCLAIMS ANY WARRANTIES, EXPRESS OR IMPLIED, WITH REGARD - TO THIS SOFTWARE INCLUDING BUT NOT LIMITED TO THE WARRANTIES - OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. - -****************************************************************************/ - -/**************************************************************************** - * Header: remcom.c,v 1.34 91/03/09 12:29:49 glenne Exp $ - * - * Module name: remcom.c $ - * Revision: 1.34 $ - * Date: 91/03/09 12:29:49 $ - * Contributor: Lake Stevens Instrument Division$ - * - * Description: low level support for gdb debugger. $ - * - * Considerations: only works on target hardware $ - * - * Written by: Glenn Engel $ - * ModuleState: Experimental $ - * - * NOTES: See Below $ - * - * Modified for M32R by Michael Snyder, Cygnus Support. - * - * To enable debugger support, two things need to happen. One, a - * call to set_debug_traps() is necessary in order to allow any breakpoints - * or error conditions to be properly intercepted and reported to gdb. - * Two, a breakpoint needs to be generated to begin communication. This - * is most easily accomplished by a call to breakpoint(). Breakpoint() - * simulates a breakpoint by executing a trap #1. - * - * The external function exceptionHandler() is - * used to attach a specific handler to a specific M32R vector number. - * It should use the same privilege level it runs at. It should - * install it as an interrupt gate so that interrupts are masked - * while the handler runs. - * - * Because gdb will sometimes write to the stack area to execute function - * calls, this program cannot rely on using the supervisor stack so it - * uses it's own stack area reserved in the int array remcomStack. - * - ************* - * - * The following gdb commands are supported: - * - * command function Return value - * - * g return the value of the CPU registers hex data or ENN - * G set the value of the CPU registers OK or ENN - * - * mAA..AA,LLLL Read LLLL bytes at address AA..AA hex data or ENN - * MAA..AA,LLLL: Write LLLL bytes at address AA.AA OK or ENN - * - * c Resume at current address SNN ( signal NN) - * cAA..AA Continue at address AA..AA SNN - * - * s Step one instruction SNN - * sAA..AA Step one instruction from AA..AA SNN - * - * k kill - * - * ? What was the last sigval ? SNN (signal NN) - * - * All commands and responses are sent with a packet which includes a - * checksum. A packet consists of - * - * $<packet info>#<checksum>. - * - * where - * <packet info> :: <characters representing the command or response> - * <checksum> :: <two hex digits computed as modulo 256 sum of <packetinfo>> - * - * When a packet is received, it is first acknowledged with either '+' or '-'. - * '+' indicates a successful transfer. '-' indicates a failed transfer. - * - * Example: - * - * Host: Reply: - * $m0,10#2a +$00010203040506070809101112131415#42 - * - ****************************************************************************/ - - -/************************************************************************ - * - * external low-level support routines - */ -extern void putDebugChar(); /* write a single character */ -extern int getDebugChar(); /* read and return a single char */ -extern void exceptionHandler(); /* assign an exception handler */ - -/***************************************************************************** - * BUFMAX defines the maximum number of characters in inbound/outbound buffers - * at least NUMREGBYTES*2 are needed for register packets - */ -#define BUFMAX 400 - -static char initialized; /* boolean flag. != 0 means we've been initialized */ - -int remote_debug; -/* debug > 0 prints ill-formed commands in valid packets & checksum errors */ - -static const char hexchars[]="0123456789abcdef"; - -#define NUMREGS 24 - -/* Number of bytes of registers. */ -#define NUMREGBYTES (NUMREGS * 4) -enum regnames { R0, R1, R2, R3, R4, R5, R6, R7, - R8, R9, R10, R11, R12, R13, R14, R15, - PSW, CBR, SPI, SPU, BPC, PC, ACCL, ACCH }; - -enum SYS_calls { - SYS_null, - SYS_exit, - SYS_open, - SYS_close, - SYS_read, - SYS_write, - SYS_lseek, - SYS_unlink, - SYS_getpid, - SYS_kill, - SYS_fstat, - SYS_sbrk, - SYS_fork, - SYS_execve, - SYS_wait4, - SYS_link, - SYS_chdir, - SYS_stat, - SYS_utime, - SYS_chown, - SYS_chmod, - SYS_time, - SYS_pipe }; - -static int registers[NUMREGS]; - -#define STACKSIZE 8096 -static char remcomInBuffer[BUFMAX]; -static char remcomOutBuffer[BUFMAX]; -static int remcomStack[STACKSIZE/sizeof(int)]; -static int* stackPtr = &remcomStack[STACKSIZE/sizeof(int) - 1]; - -static unsigned int save_vectors[18]; /* previous exception vectors */ - -/* Indicate to caller of mem2hex or hex2mem that there has been an error. */ -static volatile int mem_err = 0; - -/* Store the vector number here (since GDB only gets the signal - number through the usual means, and that's not very specific). */ -int gdb_m32r_vector = -1; - -#if 0 -#include "syscall.h" /* for SYS_exit, SYS_write etc. */ -#endif - -/* Global entry points: - */ - -extern void handle_exception(int); -extern void set_debug_traps(void); -extern void breakpoint(void); - -/* Local functions: - */ - -static int computeSignal(int); -static void putpacket(char *); -static void getpacket(char *); -static char *mem2hex(char *, char *, int, int); -static char *hex2mem(char *, char *, int, int); -static int hexToInt(char **, int *); -static void stash_registers(void); -static void restore_registers(void); -static int prepare_to_step(int); -static int finish_from_step(void); - -static void gdb_error(char *, char *); -static int gdb_putchar(int), gdb_puts(char *), gdb_write(char *, int); - -static char *strcpy (char *, const char *); -static int strlen (const char *); - -/* - * This function does all command procesing for interfacing to gdb. - */ - -void -handle_exception(int exceptionVector) -{ - int sigval; - int addr, length, i; - char * ptr; - char buf[16]; - - if (!finish_from_step()) - return; /* "false step": let the target continue */ - - gdb_m32r_vector = exceptionVector; - - if (remote_debug) - { - mem2hex((char *) &exceptionVector, buf, 4, 0); - gdb_error("Handle exception %s, ", buf); - mem2hex((char *) ®isters[PC], buf, 4, 0); - gdb_error("PC == 0x%s\n", buf); - } - - /* reply to host that an exception has occurred */ - sigval = computeSignal( exceptionVector ); - - ptr = remcomOutBuffer; - - *ptr++ = 'T'; /* notify gdb with signo, PC, FP and SP */ - *ptr++ = hexchars[sigval >> 4]; - *ptr++ = hexchars[sigval & 0xf]; - - *ptr++ = hexchars[PC >> 4]; - *ptr++ = hexchars[PC & 0xf]; - *ptr++ = ':'; - ptr = mem2hex((char *)®isters[PC], ptr, 4, 0); /* PC */ - *ptr++ = ';'; - - *ptr++ = hexchars[R13 >> 4]; - *ptr++ = hexchars[R13 & 0xf]; - *ptr++ = ':'; - ptr = mem2hex((char *)®isters[R13], ptr, 4, 0); /* FP */ - *ptr++ = ';'; - - *ptr++ = hexchars[R15 >> 4]; - *ptr++ = hexchars[R15 & 0xf]; - *ptr++ = ':'; - ptr = mem2hex((char *)®isters[R15], ptr, 4, 0); /* SP */ - *ptr++ = ';'; - *ptr++ = 0; - - if (exceptionVector == 0) /* simulated SYS call stuff */ - { - mem2hex((char *) ®isters[PC], buf, 4, 0); - switch (registers[R0]) { - case SYS_exit: - gdb_error("Target program has exited at %s\n", buf); - ptr = remcomOutBuffer; - *ptr++ = 'W'; - sigval = registers[R1] & 0xff; - *ptr++ = hexchars[sigval >> 4]; - *ptr++ = hexchars[sigval & 0xf]; - *ptr++ = 0; - break; - case SYS_open: - gdb_error("Target attempts SYS_open call at %s\n", buf); - break; - case SYS_close: - gdb_error("Target attempts SYS_close call at %s\n", buf); - break; - case SYS_read: - gdb_error("Target attempts SYS_read call at %s\n", buf); - break; - case SYS_write: - if (registers[R1] == 1 || /* write to stdout */ - registers[R1] == 2) /* write to stderr */ - { /* (we can do that) */ - registers[R0] = gdb_write((void *) registers[R2], registers[R3]); - return; - } - else - gdb_error("Target attempts SYS_write call at %s\n", buf); - break; - case SYS_lseek: - gdb_error("Target attempts SYS_lseek call at %s\n", buf); - break; - case SYS_unlink: - gdb_error("Target attempts SYS_unlink call at %s\n", buf); - break; - case SYS_getpid: - gdb_error("Target attempts SYS_getpid call at %s\n", buf); - break; - case SYS_kill: - gdb_error("Target attempts SYS_kill call at %s\n", buf); - break; - case SYS_fstat: - gdb_error("Target attempts SYS_fstat call at %s\n", buf); - break; - default: - gdb_error("Target attempts unknown SYS call at %s\n", buf); - break; - } - } - - putpacket(remcomOutBuffer); - - while (1==1) { - remcomOutBuffer[0] = 0; - getpacket(remcomInBuffer); - switch (remcomInBuffer[0]) { - default: /* Unknown code. Return an empty reply message. */ - break; - case 'R': - ptr = &remcomInBuffer[1]; - if (hexToInt (&ptr, &addr)) - registers[PC] = addr; - strcpy(remcomOutBuffer, "OK"); - break; - case '!': - strcpy(remcomOutBuffer, "OK"); - break; - case 'M': /* MAA..AA,LLLL: Write LLLL bytes at address AA.AA return OK */ - /* TRY TO READ '%x,%x:'. IF SUCCEED, SET PTR = 0 */ - ptr = &remcomInBuffer[1]; - if (hexToInt(&ptr,&addr)) - if (*(ptr++) == ',') - if (hexToInt(&ptr,&length)) - if (*(ptr++) == ':') - { - mem_err = 0; - hex2mem(ptr, (char*) addr, length, 1); - if (mem_err) { - strcpy (remcomOutBuffer, "E03"); - gdb_error ("memory fault", ""); - } else { - strcpy(remcomOutBuffer,"OK"); - } - ptr = 0; - } - if (ptr) - { - strcpy(remcomOutBuffer,"E02"); - gdb_error("malformed write memory command: %s", - remcomInBuffer); - } - break; - case 'm': /* mAA..AA,LLLL Read LLLL bytes at address AA..AA */ - /* TRY TO READ %x,%x. IF SUCCEED, SET PTR = 0 */ - ptr = &remcomInBuffer[1]; - if (hexToInt(&ptr,&addr)) - if (*(ptr++) == ',') - if (hexToInt(&ptr,&length)) - { - ptr = 0; - mem_err = 0; - mem2hex((char*) addr, remcomOutBuffer, length, 1); - if (mem_err) { - strcpy (remcomOutBuffer, "E03"); - gdb_error ("memory fault", ""); - } - } - if (ptr) - { - strcpy(remcomOutBuffer,"E01"); - gdb_error("malformed read memory command: %s", - remcomInBuffer); - } - break; - case '?': - remcomOutBuffer[0] = 'S'; - remcomOutBuffer[1] = hexchars[sigval >> 4]; - remcomOutBuffer[2] = hexchars[sigval % 16]; - remcomOutBuffer[3] = 0; - break; - case 'd': - remote_debug = !(remote_debug); /* toggle debug flag */ - break; - case 'g': /* return the value of the CPU registers */ - mem2hex((char*) registers, remcomOutBuffer, NUMREGBYTES, 0); - break; - case 'P': /* set the value of a single CPU register - return OK */ - { - int regno; - - ptr = &remcomInBuffer[1]; - if (hexToInt (&ptr, ®no) && *ptr++ == '=') - if (regno >= 0 && regno < NUMREGS) - { - int stackmode; - - hex2mem (ptr, (char *) ®isters[regno], 4, 0); - /* - * Since we just changed a single CPU register, let's - * make sure to keep the several stack pointers consistant. - */ - stackmode = registers[PSW] & 0x80; - if (regno == R15) /* stack pointer changed */ - { /* need to change SPI or SPU */ - if (stackmode == 0) - registers[SPI] = registers[R15]; - else - registers[SPU] = registers[R15]; - } - else if (regno == SPU) /* "user" stack pointer changed */ - { - if (stackmode != 0) /* stack in user mode: copy SP */ - registers[R15] = registers[SPU]; - } - else if (regno == SPI) /* "interrupt" stack pointer changed */ - { - if (stackmode == 0) /* stack in interrupt mode: copy SP */ - registers[R15] = registers[SPI]; - } - else if (regno == PSW) /* stack mode may have changed! */ - { /* force SP to either SPU or SPI */ - if (stackmode == 0) /* stack in user mode */ - registers[R15] = registers[SPI]; - else /* stack in interrupt mode */ - registers[R15] = registers[SPU]; - } - strcpy (remcomOutBuffer, "OK"); - break; - } - strcpy (remcomOutBuffer, "P01"); - break; - } - case 'G': /* set the value of the CPU registers - return OK */ - hex2mem(&remcomInBuffer[1], (char*) registers, NUMREGBYTES, 0); - strcpy(remcomOutBuffer,"OK"); - break; - case 's': /* sAA..AA Step one instruction from AA..AA(optional) */ - case 'c': /* cAA..AA Continue from address AA..AA(optional) */ - /* try to read optional parameter, pc unchanged if no parm */ - ptr = &remcomInBuffer[1]; - if (hexToInt(&ptr,&addr)) - registers[ PC ] = addr; - - if (remcomInBuffer[0] == 's') /* single-stepping */ - { - if (!prepare_to_step(0)) /* set up for single-step */ - { - /* prepare_to_step has already emulated the target insn: - Send SIGTRAP to gdb, don't resume the target at all. */ - ptr = remcomOutBuffer; - *ptr++ = 'T'; /* Simulate stopping with SIGTRAP */ - *ptr++ = '0'; - *ptr++ = '5'; - - *ptr++ = hexchars[PC >> 4]; /* send PC */ - *ptr++ = hexchars[PC & 0xf]; - *ptr++ = ':'; - ptr = mem2hex((char *)®isters[PC], ptr, 4, 0); - *ptr++ = ';'; - - *ptr++ = hexchars[R13 >> 4]; /* send FP */ - *ptr++ = hexchars[R13 & 0xf]; - *ptr++ = ':'; - ptr = mem2hex((char *)®isters[R13], ptr, 4, 0); - *ptr++ = ';'; - - *ptr++ = hexchars[R15 >> 4]; /* send SP */ - *ptr++ = hexchars[R15 & 0xf]; - *ptr++ = ':'; - ptr = mem2hex((char *)®isters[R15], ptr, 4, 0); - *ptr++ = ';'; - *ptr++ = 0; - - break; - } - } - else /* continuing, not single-stepping */ - { - /* OK, about to do a "continue". First check to see if the - target pc is on an odd boundary (second instruction in the - word). If so, we must do a single-step first, because - ya can't jump or return back to an odd boundary! */ - if ((registers[PC] & 2) != 0) - prepare_to_step(1); - } - return; - - case 'D': /* Detach */ - /* I am interpreting this to mean, release the board from control - by the remote stub. To do this, I am restoring the original - (or at least previous) exception vectors. - */ - for (i = 0; i < 18; i++) - exceptionHandler (i, save_vectors[i]); - putpacket ("OK"); - return; /* continue the inferior */ - - case 'k': /* kill the program */ - continue; - } /* switch */ - - /* reply to the request */ - putpacket(remcomOutBuffer); - } -} - -static int -hex(ch) - char ch; -{ - if ((ch >= 'a') && (ch <= 'f')) return (ch-'a'+10); - if ((ch >= '0') && (ch <= '9')) return (ch-'0'); - if ((ch >= 'A') && (ch <= 'F')) return (ch-'A'+10); - return (-1); -} - -/* scan for the sequence $<data>#<checksum> */ - -static void -getpacket(buffer) - char * buffer; -{ - unsigned char checksum; - unsigned char xmitcsum; - int i; - int count; - char ch; - - do { - /* wait around for the start character, ignore all other characters */ - while ((ch = (getDebugChar() & 0x7f)) != '$'); - checksum = 0; - xmitcsum = -1; - - count = 0; - - /* now, read until a # or end of buffer is found */ - while (count < BUFMAX) { - ch = getDebugChar() & 0x7f; - if (ch == '#') break; - checksum = checksum + ch; - buffer[count] = ch; - count = count + 1; - } - buffer[count] = 0; - - if (ch == '#') { - xmitcsum = hex(getDebugChar() & 0x7f) << 4; - xmitcsum += hex(getDebugChar() & 0x7f); - if (checksum != xmitcsum) { - if (remote_debug) { - char buf[16]; - - mem2hex((char *) &checksum, buf, 4, 0); - gdb_error("Bad checksum: my count = %s, ", buf); - mem2hex((char *) &xmitcsum, buf, 4, 0); - gdb_error("sent count = %s\n", buf); - gdb_error(" -- Bad buffer: \"%s\"\n", buffer); - } - - putDebugChar('-'); /* failed checksum */ - } else { - putDebugChar('+'); /* successful transfer */ - /* if a sequence char is present, reply the sequence ID */ - if (buffer[2] == ':') { - putDebugChar( buffer[0] ); - putDebugChar( buffer[1] ); - /* remove sequence chars from buffer */ - count = strlen(buffer); - for (i=3; i <= count; i++) buffer[i-3] = buffer[i]; - } - } - } - } while (checksum != xmitcsum); -} - -/* send the packet in buffer. */ - -static void -putpacket(buffer) - char * buffer; -{ - unsigned char checksum; - int count; - char ch; - - /* $<packet info>#<checksum>. */ - do { - putDebugChar('$'); - checksum = 0; - count = 0; - - while (ch=buffer[count]) { - putDebugChar(ch); - checksum += ch; - count += 1; - } - putDebugChar('#'); - putDebugChar(hexchars[checksum >> 4]); - putDebugChar(hexchars[checksum % 16]); - } while ((getDebugChar() & 0x7f) != '+'); -} - -/* Address of a routine to RTE to if we get a memory fault. */ - -static void (*volatile mem_fault_routine)() = 0; - -static void -set_mem_err () -{ - mem_err = 1; -} - -/* Check the address for safe access ranges. As currently defined, - this routine will reject the "expansion bus" address range(s). - To make those ranges useable, someone must implement code to detect - whether there's anything connected to the expansion bus. */ - -static int -mem_safe (addr) - char *addr; -{ -#define BAD_RANGE_ONE_START ((char *) 0x600000) -#define BAD_RANGE_ONE_END ((char *) 0xa00000) -#define BAD_RANGE_TWO_START ((char *) 0xff680000) -#define BAD_RANGE_TWO_END ((char *) 0xff800000) - - if (addr < BAD_RANGE_ONE_START) return 1; /* safe */ - if (addr < BAD_RANGE_ONE_END) return 0; /* unsafe */ - if (addr < BAD_RANGE_TWO_START) return 1; /* safe */ - if (addr < BAD_RANGE_TWO_END) return 0; /* unsafe */ -} - -/* These are separate functions so that they are so short and sweet - that the compiler won't save any registers (if there is a fault - to mem_fault, they won't get restored, so there better not be any - saved). */ -static int -get_char (addr) - char *addr; -{ -#if 1 - if (mem_fault_routine && !mem_safe(addr)) - { - mem_fault_routine (); - return 0; - } -#endif - return *addr; -} - -static void -set_char (addr, val) - char *addr; - int val; -{ -#if 1 - if (mem_fault_routine && !mem_safe (addr)) - { - mem_fault_routine (); - return; - } -#endif - *addr = val; -} - -/* Convert the memory pointed to by mem into hex, placing result in buf. - Return a pointer to the last char put in buf (null). - If MAY_FAULT is non-zero, then we should set mem_err in response to - a fault; if zero treat a fault like any other fault in the stub. */ - -static char * -mem2hex(mem, buf, count, may_fault) - char* mem; - char* buf; - int count; - int may_fault; -{ - int i; - unsigned char ch; - - if (may_fault) - mem_fault_routine = set_mem_err; - for (i=0;i<count;i++) { - ch = get_char (mem++); - if (may_fault && mem_err) - return (buf); - *buf++ = hexchars[ch >> 4]; - *buf++ = hexchars[ch % 16]; - } - *buf = 0; - if (may_fault) - mem_fault_routine = 0; - return(buf); -} - -/* Convert the hex array pointed to by buf into binary to be placed in mem. - Return a pointer to the character AFTER the last byte written. */ - -static char* -hex2mem(buf, mem, count, may_fault) - char* buf; - char* mem; - int count; - int may_fault; -{ - int i; - unsigned char ch; - - if (may_fault) - mem_fault_routine = set_mem_err; - for (i=0;i<count;i++) { - ch = hex(*buf++) << 4; - ch = ch + hex(*buf++); - set_char (mem++, ch); - if (may_fault && mem_err) - return (mem); - } - if (may_fault) - mem_fault_routine = 0; - return(mem); -} - -/* this function takes the m32r exception vector and attempts to - translate this number into a unix compatible signal value */ - -static int -computeSignal(exceptionVector) - int exceptionVector; -{ - int sigval; - switch (exceptionVector) { - case 0 : sigval = 23; break; /* I/O trap */ - case 1 : sigval = 5; break; /* breakpoint */ - case 2 : sigval = 5; break; /* breakpoint */ - case 3 : sigval = 5; break; /* breakpoint */ - case 4 : sigval = 5; break; /* breakpoint */ - case 5 : sigval = 5; break; /* breakpoint */ - case 6 : sigval = 5; break; /* breakpoint */ - case 7 : sigval = 5; break; /* breakpoint */ - case 8 : sigval = 5; break; /* breakpoint */ - case 9 : sigval = 5; break; /* breakpoint */ - case 10 : sigval = 5; break; /* breakpoint */ - case 11 : sigval = 5; break; /* breakpoint */ - case 12 : sigval = 5; break; /* breakpoint */ - case 13 : sigval = 5; break; /* breakpoint */ - case 14 : sigval = 5; break; /* breakpoint */ - case 15 : sigval = 5; break; /* breakpoint */ - case 16 : sigval = 10; break; /* BUS ERROR (alignment) */ - case 17 : sigval = 2; break; /* INTerrupt */ - default : sigval = 7; break; /* "software generated" */ - } - return (sigval); -} - -/**********************************************/ -/* WHILE WE FIND NICE HEX CHARS, BUILD AN INT */ -/* RETURN NUMBER OF CHARS PROCESSED */ -/**********************************************/ -static int -hexToInt(ptr, intValue) - char **ptr; - int *intValue; -{ - int numChars = 0; - int hexValue; - - *intValue = 0; - while (**ptr) - { - hexValue = hex(**ptr); - if (hexValue >=0) - { - *intValue = (*intValue <<4) | hexValue; - numChars ++; - } - else - break; - (*ptr)++; - } - return (numChars); -} - -/* - Table of branch instructions: - - 10B6 RTE return from trap or exception - 1FCr JMP jump - 1ECr JL jump and link - 7Fxx BRA branch - FFxxxxxx BRA branch (long) - B09rxxxx BNEZ branch not-equal-zero - Br1rxxxx BNE branch not-equal - 7Dxx BNC branch not-condition - FDxxxxxx BNC branch not-condition (long) - B0Arxxxx BLTZ branch less-than-zero - B0Crxxxx BLEZ branch less-equal-zero - 7Exx BL branch and link - FExxxxxx BL branch and link (long) - B0Drxxxx BGTZ branch greater-than-zero - B0Brxxxx BGEZ branch greater-equal-zero - B08rxxxx BEQZ branch equal-zero - Br0rxxxx BEQ branch equal - 7Cxx BC branch condition - FCxxxxxx BC branch condition (long) - */ - -static int -isShortBranch(instr) - unsigned char *instr; -{ - char instr0 = instr[0] & 0x7F; /* mask off high bit */ - - if (instr0 == 0x10 && instr[1] == 0xB6) /* RTE */ - return 1; /* return from trap or exception */ - - if (instr0 == 0x1E || instr0 == 0x1F) /* JL or JMP */ - if ((instr[1] & 0xF0) == 0xC0) - return 2; /* jump thru a register */ - - if (instr0 == 0x7C || instr0 == 0x7D || /* BC, BNC, BL, BRA */ - instr0 == 0x7E || instr0 == 0x7F) - return 3; /* eight bit PC offset */ - - return 0; -} - -static int -isLongBranch(instr) - unsigned char *instr; -{ - if (instr[0] == 0xFC || instr[0] == 0xFD || /* BRA, BNC, BL, BC */ - instr[0] == 0xFE || instr[0] == 0xFF) /* 24 bit relative */ - return 4; - if ((instr[0] & 0xF0) == 0xB0) /* 16 bit relative */ - { - if ((instr[1] & 0xF0) == 0x00 || /* BNE, BEQ */ - (instr[1] & 0xF0) == 0x10) - return 5; - if (instr[0] == 0xB0) /* BNEZ, BLTZ, BLEZ, BGTZ, BGEZ, BEQZ */ - if ((instr[1] & 0xF0) == 0x80 || (instr[1] & 0xF0) == 0x90 || - (instr[1] & 0xF0) == 0xA0 || (instr[1] & 0xF0) == 0xB0 || - (instr[1] & 0xF0) == 0xC0 || (instr[1] & 0xF0) == 0xD0) - return 6; - } - return 0; -} - -/* if address is NOT on a 4-byte boundary, or high-bit of instr is zero, - then it's a 2-byte instruction, else it's a 4-byte instruction. */ - -#define INSTRUCTION_SIZE(addr) \ - ((((int) addr & 2) || (((unsigned char *) addr)[0] & 0x80) == 0) ? 2 : 4) - -static int -isBranch(instr) - unsigned char *instr; -{ - if (INSTRUCTION_SIZE(instr) == 2) - return isShortBranch(instr); - else - return isLongBranch(instr); -} - -static int -willBranch(instr, branchCode) - unsigned char *instr; -{ - switch (branchCode) - { - case 0: return 0; /* not a branch */ - case 1: return 1; /* RTE */ - case 2: return 1; /* JL or JMP */ - case 3: /* BC, BNC, BL, BRA (short) */ - case 4: /* BC, BNC, BL, BRA (long) */ - switch (instr[0] & 0x0F) - { - case 0xC: /* Branch if Condition Register */ - return (registers[CBR] != 0); - case 0xD: /* Branch if NOT Condition Register */ - return (registers[CBR] == 0); - case 0xE: /* Branch and Link */ - case 0xF: /* Branch (unconditional) */ - return 1; - default: /* oops? */ - return 0; - } - case 5: /* BNE, BEQ */ - switch (instr[1] & 0xF0) - { - case 0x00: /* Branch if r1 equal to r2 */ - return (registers[instr[0] & 0x0F] == registers[instr[1] & 0x0F]); - case 0x10: /* Branch if r1 NOT equal to r2 */ - return (registers[instr[0] & 0x0F] != registers[instr[1] & 0x0F]); - default: /* oops? */ - return 0; - } - case 6: /* BNEZ, BLTZ, BLEZ, BGTZ, BGEZ ,BEQZ */ - switch (instr[1] & 0xF0) - { - case 0x80: /* Branch if reg equal to zero */ - return (registers[instr[1] & 0x0F] == 0); - case 0x90: /* Branch if reg NOT equal to zero */ - return (registers[instr[1] & 0x0F] != 0); - case 0xA0: /* Branch if reg less than zero */ - return (registers[instr[1] & 0x0F] < 0); - case 0xB0: /* Branch if reg greater or equal to zero */ - return (registers[instr[1] & 0x0F] >= 0); - case 0xC0: /* Branch if reg less than or equal to zero */ - return (registers[instr[1] & 0x0F] <= 0); - case 0xD0: /* Branch if reg greater than zero */ - return (registers[instr[1] & 0x0F] > 0); - default: /* oops? */ - return 0; - } - default: /* oops? */ - return 0; - } -} - -static int -branchDestination(instr, branchCode) - unsigned char *instr; -{ - switch (branchCode) { - default: - case 0: /* not a branch */ - return 0; - case 1: /* RTE */ - return registers[BPC] & ~3; /* pop BPC into PC */ - case 2: /* JL or JMP */ - return registers[instr[1] & 0x0F] & ~3; /* jump thru a register */ - case 3: /* BC, BNC, BL, BRA (short, 8-bit relative offset) */ - return (((int) instr) & ~3) + ((char) instr[1] << 2); - case 4: /* BC, BNC, BL, BRA (long, 24-bit relative offset) */ - return ((int) instr + - ((((char) instr[1] << 16) | (instr[2] << 8) | (instr[3])) << 2)); - case 5: /* BNE, BEQ (16-bit relative offset) */ - case 6: /* BNEZ, BLTZ, BLEZ, BGTZ, BGEZ ,BEQZ (ditto) */ - return ((int) instr + ((((char) instr[2] << 8) | (instr[3])) << 2)); - } - - /* An explanatory note: in the last three return expressions, I have - cast the most-significant byte of the return offset to char. - What this accomplishes is sign extension. If the other - less-significant bytes were signed as well, they would get sign - extended too and, if negative, their leading bits would clobber - the bits of the more-significant bytes ahead of them. There are - other ways I could have done this, but sign extension from - odd-sized integers is always a pain. */ -} - -static void -branchSideEffects(instr, branchCode) - char *instr; - int branchCode; -{ - switch (branchCode) - { - case 1: /* RTE */ - return; /* I <THINK> this is already handled... */ - case 2: /* JL (or JMP) */ - case 3: /* BL (or BC, BNC, BRA) */ - case 4: - if ((instr[0] & 0x0F) == 0x0E) /* branch/jump and link */ - registers[R14] = (registers[PC] & ~3) + 4; - return; - default: /* any other branch has no side effects */ - return; - } -} - -static struct STEPPING_CONTEXT { - int stepping; /* true when we've started a single-step */ - unsigned long target_addr; /* the instr we're trying to execute */ - unsigned long target_size; /* the size of the target instr */ - unsigned long noop_addr; /* where we've inserted a no-op, if any */ - unsigned long trap1_addr; /* the trap following the target instr */ - unsigned long trap2_addr; /* the trap at a branch destination, if any */ - unsigned short noop_save; /* instruction overwritten by our no-op */ - unsigned short trap1_save; /* instruction overwritten by trap1 */ - unsigned short trap2_save; /* instruction overwritten by trap2 */ - unsigned short continue_p; /* true if NOT returning to gdb after step */ -} stepping; - -/* Function: prepare_to_step - Called from handle_exception to prepare the user program to single-step. - Places a trap instruction after the target instruction, with special - extra handling for branch instructions and for instructions in the - second half-word of a word. - - Returns: True if we should actually execute the instruction; - False if we are going to emulate executing the instruction, - in which case we simply report to GDB that the instruction - has already been executed. */ - -#define TRAP1 0x10f1; /* trap #1 instruction */ -#define NOOP 0x7000; /* noop instruction */ - -static unsigned short trap1 = TRAP1; -static unsigned short noop = NOOP; - -static int -prepare_to_step(continue_p) - int continue_p; /* if this isn't REALLY a single-step (see below) */ -{ - unsigned long pc = registers[PC]; - int branchCode = isBranch((char *) pc); - char *p; - - /* zero out the stepping context - (paranoia -- it should already be zeroed) */ - for (p = (char *) &stepping; - p < ((char *) &stepping) + sizeof(stepping); - p++) - *p = 0; - - if (branchCode != 0) /* next instruction is a branch */ - { - branchSideEffects((char *) pc, branchCode); - if (willBranch((char *)pc, branchCode)) - registers[PC] = branchDestination((char *) pc, branchCode); - else - registers[PC] = pc + INSTRUCTION_SIZE(pc); - return 0; /* branch "executed" -- just notify GDB */ - } - else if (((int) pc & 2) != 0) /* "second-slot" instruction */ - { - /* insert no-op before pc */ - stepping.noop_addr = pc - 2; - stepping.noop_save = *(unsigned short *) stepping.noop_addr; - *(unsigned short *) stepping.noop_addr = noop; - /* insert trap after pc */ - stepping.trap1_addr = pc + 2; - stepping.trap1_save = *(unsigned short *) stepping.trap1_addr; - *(unsigned short *) stepping.trap1_addr = trap1; - } - else /* "first-slot" instruction */ - { - /* insert trap after pc */ - stepping.trap1_addr = pc + INSTRUCTION_SIZE(pc); - stepping.trap1_save = *(unsigned short *) stepping.trap1_addr; - *(unsigned short *) stepping.trap1_addr = trap1; - } - /* "continue_p" means that we are actually doing a continue, and not - being requested to single-step by GDB. Sometimes we have to do - one single-step before continuing, because the PC is on a half-word - boundary. There's no way to simply resume at such an address. */ - stepping.continue_p = continue_p; - stepping.stepping = 1; /* starting a single-step */ - return 1; -} - -/* Function: finish_from_step - Called from handle_exception to finish up when the user program - returns from a single-step. Replaces the instructions that had - been overwritten by traps or no-ops, - - Returns: True if we should notify GDB that the target stopped. - False if we only single-stepped because we had to before we - could continue (ie. we were trying to continue at a - half-word boundary). In that case don't notify GDB: - just "continue continuing". */ - -static int -finish_from_step() -{ - if (stepping.stepping) /* anything to do? */ - { - int continue_p = stepping.continue_p; - char *p; - - if (stepping.noop_addr) /* replace instr "under" our no-op */ - *(unsigned short *) stepping.noop_addr = stepping.noop_save; - if (stepping.trap1_addr) /* replace instr "under" our trap */ - *(unsigned short *) stepping.trap1_addr = stepping.trap1_save; - if (stepping.trap2_addr) /* ditto our other trap, if any */ - *(unsigned short *) stepping.trap2_addr = stepping.trap2_save; - - for (p = (char *) &stepping; /* zero out the stepping context */ - p < ((char *) &stepping) + sizeof(stepping); - p++) - *p = 0; - - return !(continue_p); - } - else /* we didn't single-step, therefore this must be a legitimate stop */ - return 1; -} - -struct PSWreg { /* separate out the bit flags in the PSW register */ - int pad1 : 16; - int bsm : 1; - int bie : 1; - int pad2 : 5; - int bc : 1; - int sm : 1; - int ie : 1; - int pad3 : 5; - int c : 1; -} *psw; - -/* Upon entry the value for LR to save has been pushed. - We unpush that so that the value for the stack pointer saved is correct. - Upon entry, all other registers are assumed to have not been modified - since the interrupt/trap occured. */ - -asm (" -stash_registers: - push r0 - push r1 - seth r1, #shigh(registers) - add3 r1, r1, #low(registers) - pop r0 ; r1 - st r0, @(4,r1) - pop r0 ; r0 - st r0, @r1 - addi r1, #4 ; only add 4 as subsequent saves are `pre inc' - st r2, @+r1 - st r3, @+r1 - st r4, @+r1 - st r5, @+r1 - st r6, @+r1 - st r7, @+r1 - st r8, @+r1 - st r9, @+r1 - st r10, @+r1 - st r11, @+r1 - st r12, @+r1 - st r13, @+r1 ; fp - pop r0 ; lr (r14) - st r0, @+r1 - st sp, @+r1 ; sp contains right value at this point - mvfc r0, cr0 - st r0, @+r1 ; cr0 == PSW - mvfc r0, cr1 - st r0, @+r1 ; cr1 == CBR - mvfc r0, cr2 - st r0, @+r1 ; cr2 == SPI - mvfc r0, cr3 - st r0, @+r1 ; cr3 == SPU - mvfc r0, cr6 - st r0, @+r1 ; cr6 == BPC - st r0, @+r1 ; PC == BPC - mvfaclo r0 - st r0, @+r1 ; ACCL - mvfachi r0 - st r0, @+r1 ; ACCH - jmp lr"); - -/* C routine to clean up what stash_registers did. - It is called after calling stash_registers. - This is separate from stash_registers as we want to do this in C - but doing stash_registers in C isn't straightforward. */ - -static void -cleanup_stash () -{ - psw = (struct PSWreg *) ®isters[PSW]; /* fields of PSW register */ - psw->sm = psw->bsm; /* fix up pre-trap values of psw fields */ - psw->ie = psw->bie; - psw->c = psw->bc; - registers[CBR] = psw->bc; /* fix up pre-trap "C" register */ - -#if 0 /* FIXME: Was in previous version. Necessary? - (Remember that we use the "rte" insn to return from the - trap/interrupt so the values of bsm, bie, bc are important. */ - psw->bsm = psw->bie = psw->bc = 0; /* zero post-trap values */ -#endif - - /* FIXME: Copied from previous version. This can probably be deleted - since methinks stash_registers has already done this. */ - registers[PC] = registers[BPC]; /* pre-trap PC */ - - /* FIXME: Copied from previous version. Necessary? */ - if (psw->sm) /* copy R15 into (psw->sm ? SPU : SPI) */ - registers[SPU] = registers[R15]; - else - registers[SPI] = registers[R15]; -} - -asm (" -restore_and_return: - seth r0, #shigh(registers+8) - add3 r0, r0, #low(registers+8) - ld r2, @r0+ ; restore r2 - ld r3, @r0+ ; restore r3 - ld r4, @r0+ ; restore r4 - ld r5, @r0+ ; restore r5 - ld r6, @r0+ ; restore r6 - ld r7, @r0+ ; restore r7 - ld r8, @r0+ ; restore r8 - ld r9, @r0+ ; restore r9 - ld r10, @r0+ ; restore r10 - ld r11, @r0+ ; restore r11 - ld r12, @r0+ ; restore r12 - ld r13, @r0+ ; restore r13 - ld r14, @r0+ ; restore r14 - ld r15, @r0+ ; restore r15 - ld r1, @r0+ ; restore cr0 == PSW - mvtc r1, cr0 - ld r1, @r0+ ; restore cr1 == CBR (no-op, because it's read only) - mvtc r1, cr1 - ld r1, @r0+ ; restore cr2 == SPI - mvtc r1, cr2 - ld r1, @r0+ ; restore cr3 == SPU - mvtc r1, cr3 - addi r0, #4 ; skip BPC - ld r1, @r0+ ; restore cr6 (BPC) == PC - mvtc r1, cr6 - ld r1, @r0+ ; restore ACCL - mvtaclo r1 - ld r1, @r0+ ; restore ACCH - mvtachi r1 - seth r0, #shigh(registers) - add3 r0, r0, #low(registers) - ld r1, @(4,r0) ; restore r1 - ld r0, @r0 ; restore r0 - rte"); - -/* General trap handler, called after the registers have been stashed. - NUM is the trap/exception number. */ - -static void -process_exception (num) - int num; -{ - cleanup_stash (); - asm volatile (" - seth r1, #shigh(stackPtr) - add3 r1, r1, #low(stackPtr) - ld r15, @r1 ; setup local stack (protect user stack) - mv r0, %0 - bl handle_exception - bl restore_and_return" - : : "r" (num) : "r0", "r1"); -} - -void _catchException0 (); - -asm (" -_catchException0: - push lr - bl stash_registers - ; Note that at this point the pushed value of `lr' has been popped - ldi r0, #0 - bl process_exception"); - -void _catchException1 (); - -asm (" -_catchException1: - push lr - bl stash_registers - ; Note that at this point the pushed value of `lr' has been popped - bl cleanup_stash - seth r1, #shigh(stackPtr) - add3 r1, r1, #low(stackPtr) - ld r15, @r1 ; setup local stack (protect user stack) - seth r1, #shigh(registers + 21*4) ; PC - add3 r1, r1, #low(registers + 21*4) - ld r0, @r1 - addi r0, #-4 ; back up PC for breakpoint trap. - st r0, @r1 ; FIXME: what about bp in right slot? - ldi r0, #1 - bl handle_exception - bl restore_and_return"); - -void _catchException2 (); - -asm (" -_catchException2: - push lr - bl stash_registers - ; Note that at this point the pushed value of `lr' has been popped - ldi r0, #2 - bl process_exception"); - -void _catchException3 (); - -asm (" -_catchException3: - push lr - bl stash_registers - ; Note that at this point the pushed value of `lr' has been popped - ldi r0, #3 - bl process_exception"); - -void _catchException4 (); - -asm (" -_catchException4: - push lr - bl stash_registers - ; Note that at this point the pushed value of `lr' has been popped - ldi r0, #4 - bl process_exception"); - -void _catchException5 (); - -asm (" -_catchException5: - push lr - bl stash_registers - ; Note that at this point the pushed value of `lr' has been popped - ldi r0, #5 - bl process_exception"); - -void _catchException6 (); - -asm (" -_catchException6: - push lr - bl stash_registers - ; Note that at this point the pushed value of `lr' has been popped - ldi r0, #6 - bl process_exception"); - -void _catchException7 (); - -asm (" -_catchException7: - push lr - bl stash_registers - ; Note that at this point the pushed value of `lr' has been popped - ldi r0, #7 - bl process_exception"); - -void _catchException8 (); - -asm (" -_catchException8: - push lr - bl stash_registers - ; Note that at this point the pushed value of `lr' has been popped - ldi r0, #8 - bl process_exception"); - -void _catchException9 (); - -asm (" -_catchException9: - push lr - bl stash_registers - ; Note that at this point the pushed value of `lr' has been popped - ldi r0, #9 - bl process_exception"); - -void _catchException10 (); - -asm (" -_catchException10: - push lr - bl stash_registers - ; Note that at this point the pushed value of `lr' has been popped - ldi r0, #10 - bl process_exception"); - -void _catchException11 (); - -asm (" -_catchException11: - push lr - bl stash_registers - ; Note that at this point the pushed value of `lr' has been popped - ldi r0, #11 - bl process_exception"); - -void _catchException12 (); - -asm (" -_catchException12: - push lr - bl stash_registers - ; Note that at this point the pushed value of `lr' has been popped - ldi r0, #12 - bl process_exception"); - -void _catchException13 (); - -asm (" -_catchException13: - push lr - bl stash_registers - ; Note that at this point the pushed value of `lr' has been popped - ldi r0, #13 - bl process_exception"); - -void _catchException14 (); - -asm (" -_catchException14: - push lr - bl stash_registers - ; Note that at this point the pushed value of `lr' has been popped - ldi r0, #14 - bl process_exception"); - -void _catchException15 (); - -asm (" -_catchException15: - push lr - bl stash_registers - ; Note that at this point the pushed value of `lr' has been popped - ldi r0, #15 - bl process_exception"); - -void _catchException16 (); - -asm (" -_catchException16: - push lr - bl stash_registers - ; Note that at this point the pushed value of `lr' has been popped - ldi r0, #16 - bl process_exception"); - -void _catchException17 (); - -asm (" -_catchException17: - push lr - bl stash_registers - ; Note that at this point the pushed value of `lr' has been popped - ldi r0, #17 - bl process_exception"); - - -/* this function is used to set up exception handlers for tracing and - breakpoints */ -void -set_debug_traps() -{ - /* extern void remcomHandler(); */ - int i; - - for (i = 0; i < 18; i++) /* keep a copy of old vectors */ - if (save_vectors[i] == 0) /* only copy them the first time */ - save_vectors[i] = getExceptionHandler (i); - - stackPtr = &remcomStack[STACKSIZE/sizeof(int) - 1]; - - exceptionHandler (0, _catchException0); - exceptionHandler (1, _catchException1); - exceptionHandler (2, _catchException2); - exceptionHandler (3, _catchException3); - exceptionHandler (4, _catchException4); - exceptionHandler (5, _catchException5); - exceptionHandler (6, _catchException6); - exceptionHandler (7, _catchException7); - exceptionHandler (8, _catchException8); - exceptionHandler (9, _catchException9); - exceptionHandler (10, _catchException10); - exceptionHandler (11, _catchException11); - exceptionHandler (12, _catchException12); - exceptionHandler (13, _catchException13); - exceptionHandler (14, _catchException14); - exceptionHandler (15, _catchException15); - exceptionHandler (16, _catchException16); - /* exceptionHandler (17, _catchException17); */ - - /* In case GDB is started before us, ack any packets (presumably - "$?#xx") sitting there. */ - putDebugChar ('+'); - - initialized = 1; -} - -/* This function will generate a breakpoint exception. It is used at the - beginning of a program to sync up with a debugger and can be used - otherwise as a quick means to stop program execution and "break" into - the debugger. */ - -#define BREAKPOINT() asm volatile (" trap #2"); - -void -breakpoint() -{ - if (initialized) - BREAKPOINT(); -} - -/* STDOUT section: - Stuff pertaining to simulating stdout by sending chars to gdb to be echoed. - Functions: gdb_putchar(char ch) - gdb_puts(char *str) - gdb_write(char *str, int len) - gdb_error(char *format, char *parm) - */ - -/* Function: gdb_putchar(int) - Make gdb write a char to stdout. - Returns: the char */ - -static int -gdb_putchar(ch) - int ch; -{ - char buf[4]; - - buf[0] = 'O'; - buf[1] = hexchars[ch >> 4]; - buf[2] = hexchars[ch & 0x0F]; - buf[3] = 0; - putpacket(buf); - return ch; -} - -/* Function: gdb_write(char *, int) - Make gdb write n bytes to stdout (not assumed to be null-terminated). - Returns: number of bytes written */ - -static int -gdb_write(data, len) - char *data; - int len; -{ - char *buf, *cpy; - int i; - - buf = remcomOutBuffer; - buf[0] = 'O'; - i = 0; - while (i < len) - { - for (cpy = buf+1; - i < len && cpy < buf + sizeof(remcomOutBuffer) - 3; - i++) - { - *cpy++ = hexchars[data[i] >> 4]; - *cpy++ = hexchars[data[i] & 0x0F]; - } - *cpy = 0; - putpacket(buf); - } - return len; -} - -/* Function: gdb_puts(char *) - Make gdb write a null-terminated string to stdout. - Returns: the length of the string */ - -static int -gdb_puts(str) - char *str; -{ - return gdb_write(str, strlen(str)); -} - -/* Function: gdb_error(char *, char *) - Send an error message to gdb's stdout. - First string may have 1 (one) optional "%s" in it, which - will cause the optional second string to be inserted. */ - -static void -gdb_error(format, parm) - char * format; - char * parm; -{ - char buf[400], *cpy; - int len; - - if (remote_debug) - { - if (format && *format) - len = strlen(format); - else - return; /* empty input */ - - if (parm && *parm) - len += strlen(parm); - - for (cpy = buf; *format; ) - { - if (format[0] == '%' && format[1] == 's') /* include second string */ - { - format += 2; /* advance two chars instead of just one */ - while (parm && *parm) - *cpy++ = *parm++; - } - else - *cpy++ = *format++; - } - *cpy = '\0'; - gdb_puts(buf); - } -} - -static char * -strcpy (char *dest, const char *src) -{ - char *ret = dest; - - if (dest && src) - { - while (*src) - *dest++ = *src++; - *dest = 0; - } - return ret; -} - -static int -strlen (const char *src) -{ - int ret; - - for (ret = 0; *src; src++) - ret++; - - return ret; -} - -#if 0 -void exit (code) - int code; -{ - _exit (code); -} - -int atexit (void *p) -{ - return 0; -} - -void abort (void) -{ - _exit (1); -} -#endif |