xref: /xsrc/external/mit/xorg-server/dist/hw/xfree86/x86emu/debug.c

/****************************************************************************
*
*						Realmode X86 Emulator Library
*
*            	Copyright (C) 1996-1999 SciTech Software, Inc.
* 				     Copyright (C) David Mosberger-Tang
* 					   Copyright (C) 1999 Egbert Eich
*
*  ========================================================================
*
*  Permission to use, copy, modify, distribute, and sell this software and
*  its documentation for any purpose is hereby granted without fee,
*  provided that the above copyright notice appear in all copies and that
*  both that copyright notice and this permission notice appear in
*  supporting documentation, and that the name of the authors not be used
*  in advertising or publicity pertaining to distribution of the software
*  without specific, written prior permission.  The authors makes no
*  representations about the suitability of this software for any purpose.
*  It is provided "as is" without express or implied warranty.
*
*  THE AUTHORS DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
*  INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
*  EVENT SHALL THE AUTHORS BE LIABLE FOR ANY SPECIAL, INDIRECT OR
*  CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF
*  USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
*  OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
*  PERFORMANCE OF THIS SOFTWARE.
*
*  ========================================================================
*
* Language:		ANSI C
* Environment:	Any
* Developer:    Kendall Bennett
*
* Description:  This file contains the code to handle debugging of the
*				emulator.
*
****************************************************************************/

#include "x86emu/x86emui.h"
#include <stdio.h>
#include <string.h>
#include <stdarg.h>
#ifndef NO_SYS_HEADERS
#include <stdlib.h>
#endif

/*----------------------------- Implementation ----------------------------*/

#ifdef DEBUG

static void print_encoded_bytes(u16 s, u16 o);
static void print_decoded_instruction(void);
static int parse_line(char *s, int *ps, int *n);

/* should look something like debug's output. */
void
X86EMU_trace_regs(void)
{
    if (DEBUG_TRACE()) {
        x86emu_dump_regs();
    }
    if (DEBUG_DECODE() && !DEBUG_DECODE_NOPRINT()) {
        printk("%04x:%04x ", M.x86.saved_cs, M.x86.saved_ip);
        print_encoded_bytes(M.x86.saved_cs, M.x86.saved_ip);
        print_decoded_instruction();
    }
}

void
X86EMU_trace_xregs(void)
{
    if (DEBUG_TRACE()) {
        x86emu_dump_xregs();
    }
}

void
x86emu_just_disassemble(void)
{
    /*
     * This routine called if the flag DEBUG_DISASSEMBLE is set kind
     * of a hack!
     */
    printk("%04x:%04x ", M.x86.saved_cs, M.x86.saved_ip);
    print_encoded_bytes(M.x86.saved_cs, M.x86.saved_ip);
    print_decoded_instruction();
}

static void
disassemble_forward(u16 seg, u16 off, int n)
{
    X86EMU_sysEnv tregs;
    int i;
    u8 op1;

    /*
     * hack, hack, hack.  What we do is use the exact machinery set up
     * for execution, except that now there is an additional state
     * flag associated with the "execution", and we are using a copy
     * of the register struct.  All the major opcodes, once fully
     * decoded, have the following two steps: TRACE_REGS(r,m);
     * SINGLE_STEP(r,m); which disappear if DEBUG is not defined to
     * the preprocessor.  The TRACE_REGS macro expands to:
     *
     * if (debug&DEBUG_DISASSEMBLE)
     *     {just_disassemble(); goto EndOfInstruction;}
     *     if (debug&DEBUG_TRACE) trace_regs(r,m);
     *
     * ......  and at the last line of the routine.
     *
     * EndOfInstruction: end_instr();
     *
     * Up to the point where TRACE_REG is expanded, NO modifications
     * are done to any register EXCEPT the IP register, for fetch and
     * decoding purposes.
     *
     * This was done for an entirely different reason, but makes a
     * nice way to get the system to help debug codes.
     */
    tregs = M;
    tregs.x86.R_IP = off;
    tregs.x86.R_CS = seg;

    /* reset the decoding buffers */
    tregs.x86.enc_str_pos = 0;
    tregs.x86.enc_pos = 0;

    /* turn on the "disassemble only, no execute" flag */
    tregs.x86.debug |= DEBUG_DISASSEMBLE_F;

    /* DUMP NEXT n instructions to screen in straight_line fashion */
    /*
     * This looks like the regular instruction fetch stream, except
     * that when this occurs, each fetched opcode, upon seeing the
     * DEBUG_DISASSEMBLE flag set, exits immediately after decoding
     * the instruction.  XXX --- CHECK THAT MEM IS NOT AFFECTED!!!
     * Note the use of a copy of the register structure...
     */
    for (i = 0; i < n; i++) {
        op1 = (*sys_rdb) (((u32) M.x86.R_CS << 4) + (M.x86.R_IP++));
        (x86emu_optab[op1]) (op1);
    }
    /* end major hack mode. */
}

void
x86emu_check_ip_access(void)
{
    /* NULL as of now */
}

void
x86emu_check_sp_access(void)
{
}

void
x86emu_check_mem_access(u32 dummy)
{
    /*  check bounds, etc */
}

void
x86emu_check_data_access(uint dummy1, uint dummy2)
{
    /*  check bounds, etc */
}

void
x86emu_inc_decoded_inst_len(int x)
{
    M.x86.enc_pos += x;
}

void
x86emu_decode_printf(const char *x, ...)
{
    va_list ap;
    char temp[100];

    va_start(ap, x);
    vsnprintf(temp, sizeof(temp), x, ap);
    va_end(ap);
    sprintf(M.x86.decoded_buf + M.x86.enc_str_pos, "%s", temp);
    M.x86.enc_str_pos += strlen(temp);
}

void
x86emu_end_instr(void)
{
    M.x86.enc_str_pos = 0;
    M.x86.enc_pos = 0;
}

static void
print_encoded_bytes(u16 s, u16 o)
{
    int i;
    char buf1[64];

    for (i = 0; i < M.x86.enc_pos; i++) {
        sprintf(buf1 + 2 * i, "%02x", fetch_data_byte_abs(s, o + i));
    }
    printk("%-20s", buf1);
}

static void
print_decoded_instruction(void)
{
    printk("%s", M.x86.decoded_buf);
}

void
x86emu_print_int_vect(u16 iv)
{
    u16 seg, off;

    if (iv > 256)
        return;
    seg = fetch_data_word_abs(0, iv * 4);
    off = fetch_data_word_abs(0, iv * 4 + 2);
    printk("%04x:%04x ", seg, off);
}

void
X86EMU_dump_memory(u16 seg, u16 off, u32 amt)
{
    u32 start = off & 0xfffffff0;
    u32 end = (off + 16) & 0xfffffff0;
    u32 i;

    while (end <= off + amt) {
        printk("%04x:%04x ", seg, start);
        for (i = start; i < off; i++)
            printk("   ");
        for (; i < end; i++)
            printk("%02x ", fetch_data_byte_abs(seg, i));
        printk("\n");
        start = end;
        end = start + 16;
    }
}

void
x86emu_single_step(void)
{
    char s[1024];
    int ps[10];
    int ntok;
    int cmd;
    int done;
    int segment;
    int offset;
    static int breakpoint;
    static int noDecode = 1;

    if (DEBUG_BREAK()) {
        if (M.x86.saved_ip != breakpoint) {
            return;
        }
        else {
            M.x86.debug &= ~DEBUG_DECODE_NOPRINT_F;
            M.x86.debug |= DEBUG_TRACE_F;
            M.x86.debug &= ~DEBUG_BREAK_F;
            print_decoded_instruction();
            X86EMU_trace_regs();
        }
    }
    done = 0;
    offset = M.x86.saved_ip;
    while (!done) {
        printk("-");
        (void)fgets(s, 1023, stdin);
        cmd = parse_line(s, ps, &ntok);
        switch (cmd) {
        case 'u':
            disassemble_forward(M.x86.saved_cs, (u16) offset, 10);
            break;
        case 'd':
            if (ntok == 2) {
                segment = M.x86.saved_cs;
                offset = ps[1];
                X86EMU_dump_memory(segment, (u16) offset, 16);
                offset += 16;
            }
            else if (ntok == 3) {
                segment = ps[1];
                offset = ps[2];
                X86EMU_dump_memory(segment, (u16) offset, 16);
                offset += 16;
            }
            else {
                segment = M.x86.saved_cs;
                X86EMU_dump_memory(segment, (u16) offset, 16);
                offset += 16;
            }
            break;
        case 'c':
            M.x86.debug ^= DEBUG_TRACECALL_F;
            break;
        case 's':
            M.x86.debug ^= DEBUG_SVC_F | DEBUG_SYS_F | DEBUG_SYSINT_F;
            break;
        case 'r':
            X86EMU_trace_regs();
            break;
        case 'x':
            X86EMU_trace_xregs();
            break;
        case 'g':
            if (ntok == 2) {
                breakpoint = ps[1];
                if (noDecode) {
                    M.x86.debug |= DEBUG_DECODE_NOPRINT_F;
                }
                else {
                    M.x86.debug &= ~DEBUG_DECODE_NOPRINT_F;
                }
                M.x86.debug &= ~DEBUG_TRACE_F;
                M.x86.debug |= DEBUG_BREAK_F;
                done = 1;
            }
            break;
        case 'q':
            M.x86.debug |= DEBUG_EXIT;
            return;
        case 'P':
            noDecode = (noDecode) ? 0 : 1;
            printk("Toggled decoding to %s\n", (noDecode) ? "FALSE" : "TRUE");
            break;
        case 't':
        case 0:
            done = 1;
            break;
        }
    }
}

int
X86EMU_trace_on(void)
{
    return M.x86.debug |= DEBUG_STEP_F | DEBUG_DECODE_F | DEBUG_TRACE_F;
}

int
X86EMU_trace_off(void)
{
    return M.x86.debug &= ~(DEBUG_STEP_F | DEBUG_DECODE_F | DEBUG_TRACE_F);
}

static int
parse_line(char *s, int *ps, int *n)
{
    int cmd;

    *n = 0;
    while (*s == ' ' || *s == '\t')
        s++;
    ps[*n] = *s;
    switch (*s) {
    case '\n':
        *n += 1;
        return 0;
    default:
        cmd = *s;
        *n += 1;
    }

    while (1) {
        while (*s != ' ' && *s != '\t' && *s != '\n')
            s++;

        if (*s == '\n')
            return cmd;

        while (*s == ' ' || *s == '\t')
            s++;

        sscanf(s, "%x", &ps[*n]);
        *n += 1;
    }
}

#endif                          /* DEBUG */

void
x86emu_dump_regs(void)
{
    printk("\tAX=%04x  ", M.x86.R_AX);
    printk("BX=%04x  ", M.x86.R_BX);
    printk("CX=%04x  ", M.x86.R_CX);
    printk("DX=%04x  ", M.x86.R_DX);
    printk("SP=%04x  ", M.x86.R_SP);
    printk("BP=%04x  ", M.x86.R_BP);
    printk("SI=%04x  ", M.x86.R_SI);
    printk("DI=%04x\n", M.x86.R_DI);
    printk("\tDS=%04x  ", M.x86.R_DS);
    printk("ES=%04x  ", M.x86.R_ES);
    printk("SS=%04x  ", M.x86.R_SS);
    printk("CS=%04x  ", M.x86.R_CS);
    printk("IP=%04x   ", M.x86.R_IP);
    if (ACCESS_FLAG(F_OF))
        printk("OV ");          /* CHECKED... */
    else
        printk("NV ");
    if (ACCESS_FLAG(F_DF))
        printk("DN ");
    else
        printk("UP ");
    if (ACCESS_FLAG(F_IF))
        printk("EI ");
    else
        printk("DI ");
    if (ACCESS_FLAG(F_SF))
        printk("NG ");
    else
        printk("PL ");
    if (ACCESS_FLAG(F_ZF))
        printk("ZR ");
    else
        printk("NZ ");
    if (ACCESS_FLAG(F_AF))
        printk("AC ");
    else
        printk("NA ");
    if (ACCESS_FLAG(F_PF))
        printk("PE ");
    else
        printk("PO ");
    if (ACCESS_FLAG(F_CF))
        printk("CY ");
    else
        printk("NC ");
    printk("\n");
}

void
x86emu_dump_xregs(void)
{
    printk("\tEAX=%08x  ", M.x86.R_EAX);
    printk("EBX=%08x  ", M.x86.R_EBX);
    printk("ECX=%08x  ", M.x86.R_ECX);
    printk("EDX=%08x  \n", M.x86.R_EDX);
    printk("\tESP=%08x  ", M.x86.R_ESP);
    printk("EBP=%08x  ", M.x86.R_EBP);
    printk("ESI=%08x  ", M.x86.R_ESI);
    printk("EDI=%08x\n", M.x86.R_EDI);
    printk("\tDS=%04x  ", M.x86.R_DS);
    printk("ES=%04x  ", M.x86.R_ES);
    printk("SS=%04x  ", M.x86.R_SS);
    printk("CS=%04x  ", M.x86.R_CS);
    printk("EIP=%08x\n\t", M.x86.R_EIP);
    if (ACCESS_FLAG(F_OF))
        printk("OV ");          /* CHECKED... */
    else
        printk("NV ");
    if (ACCESS_FLAG(F_DF))
        printk("DN ");
    else
        printk("UP ");
    if (ACCESS_FLAG(F_IF))
        printk("EI ");
    else
        printk("DI ");
    if (ACCESS_FLAG(F_SF))
        printk("NG ");
    else
        printk("PL ");
    if (ACCESS_FLAG(F_ZF))
        printk("ZR ");
    else
        printk("NZ ");
    if (ACCESS_FLAG(F_AF))
        printk("AC ");
    else
        printk("NA ");
    if (ACCESS_FLAG(F_PF))
        printk("PE ");
    else
        printk("PO ");
    if (ACCESS_FLAG(F_CF))
        printk("CY ");
    else
        printk("NC ");
    printk("\n");
}