ops.c

MIPS处理器的bootloader,龙芯就是用的修改过的PMON2

            u32 res;
            s16 imm;

            destreg = DECODE_RM_WORD_REGISTER(rh);
            DECODE_PRINTF(",");
            srcoffset = decode_rm10_address(rl);
            srcval = fetch_data_word(srcoffset);
            imm = fetch_word_imm();
            DECODE_PRINTF2(",%d\n", (s32)imm);
            TRACE_AND_STEP();
            res = (s16)srcval * (s16)imm;
            if (res > 0xFFFF) {
                SET_FLAG(F_CF);
                SET_FLAG(F_OF);
            } else {
                CLEAR_FLAG(F_CF);
                CLEAR_FLAG(F_OF);
            }
            *destreg = (u16)res;
        }
        break;
    case 3:                     /* register to register */
        if (M.x86.mode & SYSMODE_PREFIX_DATA) {
            u32 *destreg,*srcreg;
            u32 res_lo,res_hi;
            s32 imm;

            destreg = DECODE_RM_LONG_REGISTER(rh);
            DECODE_PRINTF(",");
            srcreg = DECODE_RM_LONG_REGISTER(rl);
            imm = fetch_long_imm();
            DECODE_PRINTF2(",%d\n", (s32)imm);
            TRACE_AND_STEP();
            imul_long_direct(&res_lo,&res_hi,(s32)*srcreg,(s32)imm);
            if (res_hi != 0) {
                SET_FLAG(F_CF);
                SET_FLAG(F_OF);
            } else {
                CLEAR_FLAG(F_CF);
                CLEAR_FLAG(F_OF);
            }
            *destreg = (u32)res_lo;
        } else {
            u16 *destreg,*srcreg;
            u32 res;
            s16 imm;

            destreg = DECODE_RM_WORD_REGISTER(rh);
            DECODE_PRINTF(",");
            srcreg = DECODE_RM_WORD_REGISTER(rl);
            imm = fetch_word_imm();
            DECODE_PRINTF2(",%d\n", (s32)imm);
            res = (s16)*srcreg * (s16)imm;
            if (res > 0xFFFF) {
                SET_FLAG(F_CF);
                SET_FLAG(F_OF);
            } else {
                CLEAR_FLAG(F_CF);
                CLEAR_FLAG(F_OF);
            }
            *destreg = (u16)res;
        }
        break;
    }
    DECODE_CLEAR_SEGOVR();
    END_OF_INSTR();
}

/****************************************************************************
REMARKS:
Handles opcode 0x6a
****************************************************************************/
static void x86emuOp_push_byte_IMM(u8 X86EMU_UNUSED(op1))
{
    s16 imm;

    START_OF_INSTR();
    imm = (s8)fetch_byte_imm();
    DECODE_PRINTF2("PUSH\t%d\n", imm);
    TRACE_AND_STEP();
    push_word(imm);
    DECODE_CLEAR_SEGOVR();
    END_OF_INSTR();
}

/****************************************************************************
REMARKS:
Handles opcode 0x6b
****************************************************************************/
static void x86emuOp_imul_byte_IMM(u8 X86EMU_UNUSED(op1))
{
    int mod, rl, rh;
    uint srcoffset;
    s8  imm;

    START_OF_INSTR();
    DECODE_PRINTF("IMUL\t");
    FETCH_DECODE_MODRM(mod, rh, rl);
    switch (mod) {
    case 0:
        if (M.x86.mode & SYSMODE_PREFIX_DATA) {
            u32 *destreg;
            u32 srcval;
            u32 res_lo,res_hi;

            destreg = DECODE_RM_LONG_REGISTER(rh);
            DECODE_PRINTF(",");
            srcoffset = decode_rm00_address(rl);
            srcval = fetch_data_long(srcoffset);
            imm = fetch_byte_imm();
            DECODE_PRINTF2(",%d\n", (s32)imm);
            TRACE_AND_STEP();
            imul_long_direct(&res_lo,&res_hi,(s32)srcval,(s32)imm);
            if (res_hi != 0) {
                SET_FLAG(F_CF);
                SET_FLAG(F_OF);
            } else {
                CLEAR_FLAG(F_CF);
                CLEAR_FLAG(F_OF);
            }
            *destreg = (u32)res_lo;
        } else {
            u16 *destreg;
            u16 srcval;
            u32 res;

            destreg = DECODE_RM_WORD_REGISTER(rh);
            DECODE_PRINTF(",");
            srcoffset = decode_rm00_address(rl);
            srcval = fetch_data_word(srcoffset);
            imm = fetch_byte_imm();
            DECODE_PRINTF2(",%d\n", (s32)imm);
            TRACE_AND_STEP();
            res = (s16)srcval * (s16)imm;
            if (res > 0xFFFF) {
                SET_FLAG(F_CF);
                SET_FLAG(F_OF);
            } else {
                CLEAR_FLAG(F_CF);
                CLEAR_FLAG(F_OF);
            }
            *destreg = (u16)res;
        }
        break;
    case 1:
        if (M.x86.mode & SYSMODE_PREFIX_DATA) {
            u32 *destreg;
            u32 srcval;
            u32 res_lo,res_hi;

            destreg = DECODE_RM_LONG_REGISTER(rh);
            DECODE_PRINTF(",");
            srcoffset = decode_rm01_address(rl);
            srcval = fetch_data_long(srcoffset);
            imm = fetch_byte_imm();
            DECODE_PRINTF2(",%d\n", (s32)imm);
            TRACE_AND_STEP();
            imul_long_direct(&res_lo,&res_hi,(s32)srcval,(s32)imm);
            if (res_hi != 0) {
                SET_FLAG(F_CF);
                SET_FLAG(F_OF);
            } else {
                CLEAR_FLAG(F_CF);
                CLEAR_FLAG(F_OF);
            }
            *destreg = (u32)res_lo;
        } else {
            u16 *destreg;
            u16 srcval;
            u32 res;

            destreg = DECODE_RM_WORD_REGISTER(rh);
            DECODE_PRINTF(",");
            srcoffset = decode_rm01_address(rl);
            srcval = fetch_data_word(srcoffset);
            imm = fetch_byte_imm();
            DECODE_PRINTF2(",%d\n", (s32)imm);
            TRACE_AND_STEP();
            res = (s16)srcval * (s16)imm;
            if (res > 0xFFFF) {
                SET_FLAG(F_CF);
                SET_FLAG(F_OF);
            } else {
                CLEAR_FLAG(F_CF);
                CLEAR_FLAG(F_OF);
            }
            *destreg = (u16)res;
        }
        break;
    case 2:
        if (M.x86.mode & SYSMODE_PREFIX_DATA) {
            u32 *destreg;
            u32 srcval;
            u32 res_lo,res_hi;

            destreg = DECODE_RM_LONG_REGISTER(rh);
            DECODE_PRINTF(",");
            srcoffset = decode_rm10_address(rl);
            srcval = fetch_data_long(srcoffset);
            imm = fetch_byte_imm();
            DECODE_PRINTF2(",%d\n", (s32)imm);
            TRACE_AND_STEP();
            imul_long_direct(&res_lo,&res_hi,(s32)srcval,(s32)imm);
            if (res_hi != 0) {
                SET_FLAG(F_CF);
                SET_FLAG(F_OF);
            } else {
                CLEAR_FLAG(F_CF);
                CLEAR_FLAG(F_OF);
            }
            *destreg = (u32)res_lo;
        } else {
            u16 *destreg;
            u16 srcval;
            u32 res;

            destreg = DECODE_RM_WORD_REGISTER(rh);
            DECODE_PRINTF(",");
            srcoffset = decode_rm10_address(rl);
            srcval = fetch_data_word(srcoffset);
            imm = fetch_byte_imm();
            DECODE_PRINTF2(",%d\n", (s32)imm);
            TRACE_AND_STEP();
            res = (s16)srcval * (s16)imm;
            if (res > 0xFFFF) {
                SET_FLAG(F_CF);
                SET_FLAG(F_OF);
            } else {
                CLEAR_FLAG(F_CF);
                CLEAR_FLAG(F_OF);
            }
            *destreg = (u16)res;
        }
        break;
    case 3:                     /* register to register */
        if (M.x86.mode & SYSMODE_PREFIX_DATA) {
            u32 *destreg,*srcreg;
            u32 res_lo,res_hi;

            destreg = DECODE_RM_LONG_REGISTER(rh);
            DECODE_PRINTF(",");
            srcreg = DECODE_RM_LONG_REGISTER(rl);
            imm = fetch_byte_imm();
            DECODE_PRINTF2(",%d\n", (s32)imm);
            TRACE_AND_STEP();
            imul_long_direct(&res_lo,&res_hi,(s32)*srcreg,(s32)imm);
            if (res_hi != 0) {
                SET_FLAG(F_CF);
                SET_FLAG(F_OF);
            } else {
                CLEAR_FLAG(F_CF);
                CLEAR_FLAG(F_OF);
            }
            *destreg = (u32)res_lo;
        } else {
            u16 *destreg,*srcreg;
            u32 res;

            destreg = DECODE_RM_WORD_REGISTER(rh);
            DECODE_PRINTF(",");
            srcreg = DECODE_RM_WORD_REGISTER(rl);
            imm = fetch_byte_imm();
            DECODE_PRINTF2(",%d\n", (s32)imm);
            res = (s16)*srcreg * (s16)imm;
            if (res > 0xFFFF) {
                SET_FLAG(F_CF);
                SET_FLAG(F_OF);
            } else {
                CLEAR_FLAG(F_CF);
                CLEAR_FLAG(F_OF);
            }
            *destreg = (u16)res;
        }
        break;
    }
    DECODE_CLEAR_SEGOVR();
    END_OF_INSTR();
}

/****************************************************************************
REMARKS:
Handles opcode 0x6c
****************************************************************************/
static void x86emuOp_ins_byte(u8 X86EMU_UNUSED(op1))
{
    START_OF_INSTR();
    DECODE_PRINTF("INSB\n");
    ins(1);
    TRACE_AND_STEP();
    DECODE_CLEAR_SEGOVR();
    END_OF_INSTR();
}

/****************************************************************************
REMARKS:
Handles opcode 0x6d
****************************************************************************/
static void x86emuOp_ins_word(u8 X86EMU_UNUSED(op1))
{
    START_OF_INSTR();
    if (M.x86.mode & SYSMODE_PREFIX_DATA) {
        DECODE_PRINTF("INSD\n");
        ins(4);
    } else {
        DECODE_PRINTF("INSW\n");
        ins(2);
    }
    TRACE_AND_STEP();
    DECODE_CLEAR_SEGOVR();
    END_OF_INSTR();
}

/****************************************************************************
REMARKS:
Handles opcode 0x6e
****************************************************************************/
static void x86emuOp_outs_byte(u8 X86EMU_UNUSED(op1))
{
    START_OF_INSTR();
    DECODE_PRINTF("OUTSB\n");
    outs(1);
    TRACE_AND_STEP();
    DECODE_CLEAR_SEGOVR();
    END_OF_INSTR();
}

/****************************************************************************
REMARKS:
Handles opcode 0x6f
****************************************************************************/
static void x86emuOp_outs_word(u8 X86EMU_UNUSED(op1))
{
    START_OF_INSTR();
    if (M.x86.mode & SYSMODE_PREFIX_DATA) {
        DECODE_PRINTF("OUTSD\n");
        outs(4);
    } else {
        DECODE_PRINTF("OUTSW\n");
        outs(2);
    }
    TRACE_AND_STEP();
    DECODE_CLEAR_SEGOVR();
    END_OF_INSTR();
}

/****************************************************************************
REMARKS:
Handles opcode 0x70
****************************************************************************/
static void x86emuOp_jump_near_O(u8 X86EMU_UNUSED(op1))
{
    s8 offset;
    u16 target;

    /* jump to byte offset if overflow flag is set */
    START_OF_INSTR();
    DECODE_PRINTF("JO\t");
    offset = (s8)fetch_byte_imm();
    target = (u16)(M.x86.R_IP + (s16)offset);
    DECODE_PRINTF2("%x\n", target);
    TRACE_AND_STEP();
    if (ACCESS_FLAG(F_OF))
        M.x86.R_IP = target;
    DECODE_CLEAR_SEGOVR();
    END_OF_INSTR();
}

/****************************************************************************
REMARKS:
Handles opcode 0x71
****************************************************************************/
static void x86emuOp_jump_near_NO(u8 X86EMU_UNUSED(op1))
{
    s8 offset;
    u16 target;

    /* jump to byte offset if overflow is not set */
    START_OF_INSTR();
    DECODE_PRINTF("JNO\t");
    offset = (s8)fetch_byte_imm();
    target = (u16)(M.x86.R_IP + (s16)offset);
    DECODE_PRINTF2("%x\n", target);
    TRACE_AND_STEP();
    if (!ACCESS_FLAG(F_OF))
        M.x86.R_IP = target;
    DECODE_CLEAR_SEGOVR();
    END_OF_INSTR();
}

/****************************************************************************
REMARKS:
Handles opcode 0x72
****************************************************************************/
static void x86emuOp_jump_near_B(u8 X86EMU_UNUSED(op1))
{
    s8 offset;
    u16 target;

    /* jump to byte offset if carry flag is set. */
    START_OF_INSTR();
    DECODE_PRINTF("JB\t");
    offset = (s8)fetch_byte_imm();
    target = (u16)(M.x86.R_IP + (s16)offset);
    DECODE_PRINTF2("%x\n", target);
    TRACE_AND_STEP();
    if (ACCESS_FLAG(F_CF))
        M.x86.R_IP = target;
    DECODE_CLEAR_SEGOVR();
    END_OF_INSTR();
}

/****************************************************************************
REMARKS:
Handles opcode 0x73
****************************************************************************/
static void x86emuOp_jump_near_NB(u8 X86EMU_UNUSED(op1))
{
    s8 offset;
    u16 target;

    /* jump to byte offset if carry flag is clear. */
    START_OF_INSTR();
    DECODE_PRINTF("JNB\t");
    offset = (s8)fetch_byte_imm();
    target = (u16)(M.x86.R_IP + (s16)offset);
    DECODE_PRINTF2("%x\n", target);
    TRACE_AND_STEP();
    if (!ACCESS_FLAG(F_CF))
        M