/* vax_syscm.c: PDP-11 compatibility mode symbolic decode and parse

   Copyright (c) 1993-2006, Robert M Supnik

   Permission is hereby granted, free of charge, to any person obtaining a
   copy of this software and associated documentation files (the "Software"),
   to deal in the Software without restriction, including without limitation
   the rights to use, copy, modify, merge, publish, distribute, sublicense,
   and/or sell copies of the Software, and to permit persons to whom the
   Software is furnished to do so, subject to the following conditions:

   The above copyright notice and this permission notice shall be included in
   all copies or substantial portions of the Software.

   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
   FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
   ROBERT M SUPNIK BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
   IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
   CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

   Except as contained in this notice, the name of Robert M Supnik shall not be
   used in advertising or otherwise to promote the sale, use or other dealings
   in this Software without prior written authorization from Robert M Supnik.

   12-Nov-06    RMS     Fixed operand order in EIS instructions (found by W.F.J. Mueller)
   27-Sep-05	RMS     Fixed warnings compiling with 64b addresses
   15-Sep-04    RMS     Cloned from pdp11_sys.c
*/

#include "vax_defs.h"
#include <ctype.h>

extern UNIT cpu_unit;

/* Symbol tables */
/* Warning: for literals, the class number MUST equal the field width!! */

#define I_V_CL          18                              /* class bits */
#define I_M_CL          017                             /* class mask */
#define I_V_NPN         0                               /* no operands */
#define I_V_REG         1                               /* reg */
#define I_V_SOP         2                               /* operand */
#define I_V_3B          3                               /* 3b literal */
#define I_V_RSOP        4                               /* reg, operand */
#define I_V_BR          5                               /* cond branch */
#define I_V_6B          6                               /* 6b literal */
#define I_V_SOB         7                               /* reg, disp */
#define I_V_8B          8                               /* 8b literal */
#define I_V_DOP         9                               /* double operand */
#define I_V_CCC         10                              /* CC clear */
#define I_V_CCS         11                              /* CC set */
#define I_V_SOPR        12                              /* operand, reg */
#define I_NPN           (I_V_NPN << I_V_CL)
#define I_REG           (I_V_REG << I_V_CL)
#define I_SOP           (I_V_SOP << I_V_CL)
#define I_3B            (I_V_3B << I_V_CL)
#define I_6B            (I_V_6B << I_V_CL)
#define I_BR            (I_V_BR << I_V_CL)
#define I_8B            (I_V_8B << I_V_CL)
#define I_RSOP          (I_V_RSOP << I_V_CL)
#define I_SOB           (I_V_SOB << I_V_CL)
#define I_DOP           (I_V_DOP << I_V_CL)
#define I_CCC           (I_V_CCC << I_V_CL)
#define I_CCS           (I_V_CCS << I_V_CL)
#define I_SOPR          (I_V_SOPR << I_V_CL)

static const int32 masks[] = {
 0177777, 0177770, 0177700, 0177770,
 0177000, 0177400, 0177700, 0177000,
 0177400, 0170000, 0177777, 0177777,
 0177000
 };

static const char *opcode[] = {
"HALT","WAIT","RTI","BPT",
"IOT","RESET","RTT","MFPT",
"JMP","RTS","SPL",
"NOP","CLC","CLV","CLV CLC",
"CLZ","CLZ CLC","CLZ CLV","CLZ CLV CLC",
"CLN","CLN CLC","CLN CLV","CLN CLV CLC",
"CLN CLZ","CLN CLZ CLC","CLN CLZ CLC","CCC",
"NOP","SEC","SEV","SEV SEC",
"SEZ","SEZ SEC","SEZ SEV","SEZ SEV SEC",
"SEN","SEN SEC","SEN SEV","SEN SEV SEC",
"SEN SEZ","SEN SEZ SEC","SEN SEZ SEC","SCC",
"SWAB","BR","BNE","BEQ",
"BGE","BLT","BGT","BLE",
"JSR",
"CLR","COM","INC","DEC",
"NEG","ADC","SBC","TST",
"ROR","ROL","ASR","ASL",
"MARK","MFPI","MTPI","SXT",
"CSM",        "TSTSET","WRTLCK",
"MOV","CMP","BIT","BIC",
"BIS","ADD",
"MUL","DIV","ASH","ASHC",
"XOR",
"FADD","FSUB","FMUL","FDIV",
"L2DR",
"MOVC","MOVRC","MOVTC",
"LOCC","SKPC","SCANC","SPANC",
"CMPC","MATC",
"ADDN","SUBN","CMPN","CVTNL",
"CVTPN","CVTNP","ASHN","CVTLN",
"L3DR",
"ADDP","SUBP","CMPP","CVTPL",
"MULP","DIVP","ASHP","CVTLP",
"MOVCI","MOVRCI","MOVTCI",
"LOCCI","SKPCI","SCANCI","SPANCI",
"CMPCI","MATCI",
"ADDNI","SUBNI","CMPNI","CVTNLI",
"CVTPNI","CVTNPI","ASHNI","CVTLNI",
"ADDPI","SUBPI","CMPPI","CVTPLI",
"MULPI","DIVPI","ASHPI","CVTLPI",
"SOB",
"BPL","BMI","BHI","BLOS",
"BVC","BVS","BCC","BCS",
"BHIS","BLO",                                           /* encode only */
"EMT","TRAP",
"CLRB","COMB","INCB","DECB",
"NEGB","ADCB","SBCB","TSTB",
"RORB","ROLB","ASRB","ASLB",
"MTPS","MFPD","MTPD","MFPS",
"MOVB","CMPB","BITB","BICB",
"BISB","SUB",
NULL
};

static const int32 opc_val[] = {
0000000+I_NPN, 0000001+I_NPN, 0000002+I_NPN, 0000003+I_NPN,
0000004+I_NPN, 0000005+I_NPN, 0000006+I_NPN, 0000007+I_NPN,
0000100+I_SOP, 0000200+I_REG, 0000230+I_3B,
0000240+I_CCC, 0000241+I_CCC, 0000242+I_CCC, 0000243+I_NPN, 
0000244+I_CCC, 0000245+I_NPN, 0000246+I_NPN, 0000247+I_NPN, 
0000250+I_CCC, 0000251+I_NPN, 0000252+I_NPN, 0000253+I_NPN, 
0000254+I_NPN, 0000255+I_NPN, 0000256+I_NPN, 0000257+I_CCC, 
0000260+I_CCS, 0000261+I_CCS, 0000262+I_CCS, 0000263+I_NPN, 
0000264+I_CCS, 0000265+I_NPN, 0000266+I_NPN, 0000267+I_NPN, 
0000270+I_CCS, 0000271+I_NPN, 0000272+I_NPN, 0000273+I_NPN, 
0000274+I_NPN, 0000275+I_NPN, 0000276+I_NPN, 0000277+I_CCS, 
0000300+I_SOP, 0000400+I_BR, 0001000+I_BR, 0001400+I_BR,
0002000+I_BR, 0002400+I_BR, 0003000+I_BR, 0003400+I_BR,
0004000+I_RSOP,
0005000+I_SOP, 0005100+I_SOP, 0005200+I_SOP, 0005300+I_SOP,
0005400+I_SOP, 0005500+I_SOP, 0005600+I_SOP, 0005700+I_SOP,
0006000+I_SOP, 0006100+I_SOP, 0006200+I_SOP, 0006300+I_SOP,
0006400+I_6B, 0006500+I_SOP, 0006600+I_SOP, 0006700+I_SOP,
0007000+I_SOP,                0007200+I_SOP, 0007300+I_SOP,
0010000+I_DOP, 0020000+I_DOP, 0030000+I_DOP, 0040000+I_DOP,
0050000+I_DOP, 0060000+I_DOP,
0070000+I_SOPR, 0071000+I_SOPR, 0072000+I_SOPR, 0073000+I_SOPR,
0074000+I_RSOP,
0075000+I_REG, 0075010+I_REG, 0075020+I_REG, 0075030+I_REG,
0076020+I_REG,
0076030+I_NPN, 0076031+I_NPN, 0076032+I_NPN,
0076040+I_NPN, 0076041+I_NPN, 0076042+I_NPN, 0076043+I_NPN,
0076044+I_NPN, 0076045+I_NPN, 
0076050+I_NPN, 0076051+I_NPN, 0076052+I_NPN, 0076053+I_NPN,
0076054+I_NPN, 0076055+I_NPN, 0076056+I_NPN, 0076057+I_NPN,
0076060+I_REG,
0076070+I_NPN, 0076071+I_NPN, 0076072+I_NPN, 0076073+I_NPN,
0076074+I_NPN, 0076075+I_NPN, 0076076+I_NPN, 0076077+I_NPN,
0076130+I_NPN, 0076131+I_NPN, 0076132+I_NPN,
0076140+I_NPN, 0076141+I_NPN, 0076142+I_NPN, 0076143+I_NPN,
0076144+I_NPN, 0076145+I_NPN, 
0076150+I_NPN, 0076151+I_NPN, 0076152+I_NPN, 0076153+I_NPN,
0076154+I_NPN, 0076155+I_NPN, 0076156+I_NPN, 0076157+I_NPN,
0076170+I_NPN, 0076171+I_NPN, 0076172+I_NPN, 0076173+I_NPN,
0076174+I_NPN, 0076175+I_NPN, 0076176+I_NPN, 0076177+I_NPN,
0077000+I_SOB,
0100000+I_BR, 0100400+I_BR, 0101000+I_BR, 0101400+I_BR,
0102000+I_BR, 0102400+I_BR, 0103000+I_BR, 0103400+I_BR,
0103000+I_BR, 0103400+I_BR,
0104000+I_8B, 0104400+I_8B,
0105000+I_SOP, 0105100+I_SOP, 0105200+I_SOP, 0105300+I_SOP,
0105400+I_SOP, 0105500+I_SOP, 0105600+I_SOP, 0105700+I_SOP,
0106000+I_SOP, 0106100+I_SOP, 0106200+I_SOP, 0106300+I_SOP,
0106400+I_SOP, 0106500+I_SOP, 0106600+I_SOP, 0106700+I_SOP,
0110000+I_DOP, 0120000+I_DOP, 0130000+I_DOP, 0140000+I_DOP,
0150000+I_DOP, 0160000+I_DOP,
-1
};

static const char *rname [] = {
 "R0", "R1", "R2", "R3", "R4", "R5", "SP", "PC"
 };

static const char r50_to_asc[] = " ABCDEFGHIJKLMNOPQRSTUVWXYZ$._0123456789";

/* Specifier decode

   Inputs:
        *of     =       output stream
        addr    =       current PC
        spec    =       specifier
        nval    =       next word
        flag    =       TRUE if decoding for CPU
        iflag   =       TRUE if decoding integer instruction
   Outputs:
        count   =       -number of extra words retired
*/

int32 fprint_spec (FILE *of, t_addr addr, int32 spec, int32 nval)
{
int32 reg, mode;
static const int32 rgwd[8] = { 0, 0, 0, 0, 0, 0, -1, -1 };
static const int32 pcwd[8] = { 0, 0, -1, -1, 0, 0, -1, -1 };

reg = spec & 07;
mode = ((spec >> 3) & 07);
switch (mode) {

    case 0:
        fprintf (of, "%s", rname[reg]);
        break;

    case 1:
        fprintf (of, "(%s)", rname[reg]);
        break;

    case 2:
        if (reg != 7) fprintf (of, "(%s)+", rname[reg]);
        else fprintf (of, "#%-X", nval);
        break;

    case 3:
        if (reg != 7) fprintf (of, "@(%s)+", rname[reg]);
        else fprintf (of, "@#%-X", nval);
        break;

    case 4:
        fprintf (of, "-(%s)", rname[reg]);
        break;

    case 5:
        fprintf (of, "@-(%s)", rname[reg]);
        break;

    case 6:
        if (reg != 7) fprintf (of, "%-X(%s)", nval, rname[reg]);
        else fprintf (of, "%-X", (nval + addr + 4) & 0177777);
        break;

    case 7:
        if (reg != 7) fprintf (of, "@%-X(%s)", nval, rname[reg]);
        else fprintf (of, "@%-X", (nval + addr + 4) & 0177777);
        break;
        }                                               /* end case */

return ((reg == 07)? pcwd[mode]: rgwd[mode]);
}

/* Symbolic decode

   Inputs:
        *of     =       output stream
        addr    =       current PC
        *val    =       values to decode
        *uptr   =       pointer to unit
        sw      =       switches
   Outputs:
        return  =       if >= 0, error code
                        if < 0, number of extra words retired
*/

t_stat fprint_sym_cm (FILE *of, t_addr addr, t_value *bytes, int32 sw)
{
int32 i, j, c1, c2, c3, inst, srcm, srcr, dstm, dstr;
int32 l8b, brdisp, wd1;
uint32 val[3];

for (i = j = 0; i < 3; i++, j = j + 2)
    val[i] = (int32) (bytes[j] | (bytes[j + 1] << 8));
    
if (sw & SWMASK ('R')) {                                /* radix 50? */
    if (val[0] > 0174777) return SCPE_ARG;              /* max value */
    c3 = val[0] % 050;
    c2 = (val[0] / 050) % 050;
    c1 = val[0] / (050 * 050);
    fprintf (of, "%c%c%c", r50_to_asc[c1],
            r50_to_asc[c2], r50_to_asc[c3]);
    return -1;
    }
if (!(sw & SWMASK ('P')) || (addr & 1) || (addr > WMASK))
    return SCPE_ARG;

inst = val[0];                                          /* inst */
wd1 = 0;
for (i = 0; opc_val[i] >= 0; i++) {                     /* loop thru ops */
    j = (opc_val[i] >> I_V_CL) & I_M_CL;                /* get class */
    if ((opc_val[i] & 0177777) == (inst & masks[j])) {  /* match? */
        srcm = (inst >> 6) & 077;                       /* opr fields */
        srcr = srcm & 07;
        dstm = inst & 077;
        dstr = dstm & 07;
        l8b = inst & 0377;
        switch (j) {                                    /* case on class */

            case I_V_NPN: case I_V_CCC: case I_V_CCS:   /* no operands */
                fprintf (of, "%s", opcode[i]);
                break;

            case I_V_REG:                               /* reg */
                fprintf (of, "%s %-s", opcode[i], rname[dstr]);
                break;

            case I_V_SOP:                               /* sop */
                fprintf (of, "%s ", opcode[i]);
                wd1 = fprint_spec (of, addr, dstm, val[1]);
                break;

            case I_V_3B:                                /* 3b */
                fprintf (of, "%s %-X", opcode[i], dstr);
                break;

            case I_V_6B:                                /* 6b */
                fprintf (of, "%s %-X", opcode[i], dstm);
                break;

            case I_V_BR:                                /* cond branch */
                fprintf (of, "%s ", opcode[i]);
                brdisp = (l8b + l8b + ((l8b & 0200)? 0177002: 2)) & 0177777;
                fprintf (of, "%-X", (addr + brdisp) & 0177777);
                break;

            case I_V_8B:                                /* 8b */
                fprintf (of, "%s %-X", opcode[i], l8b);
                break;

            case I_V_SOB:                               /* sob */
                fprintf (of, "%s %s,", opcode[i], rname[srcr]);
                brdisp = (dstm * 2) - 2;
                fprintf (of, "%-X", (addr - brdisp) & 0177777);
                break;

            case I_V_RSOP:                              /* rsop */
                fprintf (of, "%s %s,", opcode[i], rname[srcr]);
                wd1 = fprint_spec (of, addr, dstm, val[1]);
                break;

            case I_V_SOPR:                              /* sopr */
                fprintf (of, "%s ", opcode[i]);
                wd1 = fprint_spec (of, addr, dstm, val[1]);
                fprintf (of, ",%s", rname[srcr]);
                break;

            case I_V_DOP:                               /* dop */
                fprintf (of, "%s ", opcode[i]);
                wd1 = fprint_spec (of, addr, srcm, val[1]);
                fprintf (of, ",");
                wd1 += fprint_spec (of, addr - wd1 - wd1, dstm,
                    val[1 - wd1]);
                break;
                }                                       /* end case */

        return ((wd1 * 2) - 1);
        }                                               /* end if */
    }                                                   /* end for */
return SCPE_ARG;                                        /* no match */
}

#define A_PND   100                                     /* # seen */
#define A_MIN   040                                     /* -( seen */
#define A_PAR   020                                     /* (Rn) seen */
#define A_REG   010                                     /* Rn seen */
#define A_PLS   004                                     /* + seen */
#define A_NUM   002                                     /* number seen */
#define A_REL   001                                     /* relative addr seen */

/* Register number

   Inputs:
        *cptr   =       pointer to input string
        mchar   =       character to match after register name
   Outputs:
        rnum    =       0..7 if a legitimate register
                        < 0 if error
*/

int32 get_reg (char *cptr, char mchar)
{
int32 i;

if (*(cptr + 2) != mchar) return -1;
for (i = 0; i < 8; i++) {
    if (strncmp (cptr, rname[i], 2) == 0) return i;
    }
return -1;
}

/* Number or memory address

   Inputs:
        *cptr   =       pointer to input string
        *dptr   =       pointer to output displacement
        *pflag  =       pointer to accumulating flags
   Outputs:
        cptr    =       pointer to next character in input string
                        NULL if parsing error

   Flags: 0 (no result), A_NUM (number), A_REL (relative)
*/

char *get_addr (char *cptr, int32 *dptr, int32 *pflag)
{
int32 val, minus;
char *tptr;

minus = 0;

if (*cptr == '.') {                                     /* relative? */
    *pflag = *pflag | A_REL;
    cptr++;
    }
if (*cptr == '+') {                                     /* +? */
    *pflag = *pflag | A_NUM;
    cptr++;
    }
if (*cptr == '-') {                                     /* -? */
    *pflag = *pflag | A_NUM;
    minus = 1;
    cptr++;
    }
errno = 0;
val = strtoul (cptr, &tptr, 16);
if (cptr == tptr) {                                     /* no number? */
    if (*pflag == (A_REL + A_NUM)) return NULL;         /* .+, .-? */
    *dptr = 0;
    return cptr;
    }
if (errno || (*pflag == A_REL)) return NULL;            /* .n? */
*dptr = (minus? -val: val) & 0177777;
*pflag = *pflag | A_NUM;
return tptr;
}

/* Specifier decode

   Inputs:
        *cptr   =       pointer to input string
        addr    =       current PC
        n1      =       0 if no extra word used
                        -1 if extra word used in prior decode
        *sptr   =       pointer to output specifier
        *dptr   =       pointer to output displacement
   Outputs:
        status  =       = -1 extra word decoded
                        =  0 ok
                        = +1 error
*/

t_stat get_spec (char *cptr, int32 addr, int32 n1, int32 *sptr, int32 *dptr)
{
int32 reg, indir, pflag, disp;

indir = 0;                                              /* no indirect */
pflag = 0;

if (*cptr == '@') {                                     /* indirect? */
    indir = 010;
    cptr++;
    }
if (*cptr == '#') {                                     /* literal? */
    pflag = pflag | A_PND;
    cptr++;
    }
if (strncmp (cptr, "-(", 2) == 0) {                     /* autodecrement? */
    pflag = pflag | A_MIN;
    cptr++;
    }
else if ((cptr = get_addr (cptr, &disp, &pflag)) == NULL) return 1;
if (*cptr == '(') {                                     /* register index? */
    pflag = pflag | A_PAR;
    if ((reg = get_reg (cptr + 1, ')')) < 0) return 1;
    cptr = cptr + 4;
    if (*cptr == '+') {                                 /* autoincrement? */
        pflag = pflag | A_PLS;
        cptr++;
        }
    }
else if ((reg = get_reg (cptr, 0)) >= 0) {
    pflag = pflag | A_REG;
    cptr = cptr + 2;
    }
if (*cptr != 0) return 1;                               /* all done? */

switch (pflag) {                                        /* case on syntax */

    case A_REG:                                         /* Rn, @Rn */
        *sptr = indir + reg;
        return 0;

    case A_PAR:                                         /* (Rn), @(Rn) */
        if (indir) {                                    /* @(Rn) = @0(Rn) */
            *sptr = 070 + reg;
            *dptr = 0;
            return -1;
            }
        else *sptr = 010 + reg;
        return 0;

    case A_PAR+A_PLS:                                   /* (Rn)+, @(Rn)+ */
        *sptr = 020 + indir + reg;
        return 0;

    case A_MIN+A_PAR:                                   /* -(Rn), @-(Rn) */
        *sptr = 040 + indir + reg;
        return 0;

    case A_NUM+A_PAR:                                   /* d(Rn), @d(Rn) */
        *sptr = 060 + indir + reg;
        *dptr = disp;
        return -1;

    case A_PND+A_REL: case A_PND+A_REL+A_NUM:           /* #.+n, @#.+n */
        disp = (disp + addr) & 0177777;                 /* fall through */
    case A_PND+A_NUM:                                   /* #n, @#n */
        *sptr = 027 + indir;
        *dptr = disp;
        return -1;

    case A_REL: case A_REL+A_NUM:                       /* .+n, @.+n */
        *sptr = 067 + indir;
        *dptr = (disp - 4 + (2 * n1)) & 0177777;
        return -1;

    case A_NUM:                                         /* n, @n */
        *sptr = 067 + indir;
        *dptr = (disp - addr - 4 + (2 * n1)) & 0177777;
        return -1;

    default:
        return 1;
        }                                               /* end case */
}

/* Symbolic input

   Inputs:
        *cptr   =       pointer to input string
        addr    =       current PC
        *uptr   =       pointer to unit
        *val    =       pointer to output values
        sw      =       switches
   Outputs:
        status  =       > 0   error code
                        <= 0  -number of extra words
*/

t_stat parse_sym_cm (char *cptr, t_addr addr, t_value *bytes, int32 sw)
{
int32 d, i, j, reg, spec, n1, n2, disp, pflag;
int32 val[3];
int32 ad32 = (int32) addr;
t_stat r;
char *tptr, gbuf[CBUFSIZE];

if (sw & SWMASK ('R')) return SCPE_ARG;                 /* radix 50 */
if (!(sw & SWMASK ('P')) || (ad32 & 1) || (ad32 > WMASK))
    return SCPE_ARG;

cptr = get_glyph (cptr, gbuf, 0);                       /* get opcode */
n1 = n2 = pflag = 0;
for (i = 0; (opcode[i] != NULL) && (strcmp (opcode[i], gbuf) != 0) ; i++) ;
if (opcode[i] == NULL) return SCPE_ARG;
val[0] = opc_val[i] & 0177777;                          /* get value */
j = (opc_val[i] >> I_V_CL) & I_M_CL;                    /* get class */

switch (j) {                                            /* case on class */

    case I_V_NPN:                                       /* no operand */
        break;

    case I_V_REG:                                       /* register */
        cptr = get_glyph (cptr, gbuf, 0);               /* get glyph */
        if ((reg = get_reg (gbuf, 0)) < 0) return SCPE_ARG;
        val[0] = val[0] | reg;
        break;

    case I_V_3B: case I_V_6B: case I_V_8B:              /* xb literal */
        cptr = get_glyph (cptr, gbuf, 0);               /* get literal */
        d = (int32) get_uint (gbuf, 16, (1 << j) - 1, &r);
        if (r != SCPE_OK) return SCPE_ARG;
        val[0] = val[0] | d;                            /* put in place */
        break;

    case I_V_BR:                                        /* cond br */
        cptr = get_glyph (cptr, gbuf, 0);               /* get address */
        tptr = get_addr (gbuf, &disp, &pflag);          /* parse */
        if ((tptr == NULL) || (*tptr != 0)) return SCPE_ARG;
        if ((pflag & A_REL) == 0)
            disp = (disp - ad32) & 0177777;
        if ((disp & 1) || (disp > 0400) && (disp < 0177402)) return SCPE_ARG;
        val[0] = val[0] | (((disp - 2) >> 1) & 0377);
        break;

    case I_V_SOB:                                       /* sob */
        cptr = get_glyph (cptr, gbuf, ',');             /* get glyph */
        if ((reg = get_reg (gbuf, 0)) < 0) return SCPE_ARG;
        val[0] = val[0] | (reg << 6);
        cptr = get_glyph (cptr, gbuf, 0);               /* get address */
        tptr = get_addr (gbuf, &disp, &pflag);          /* parse */
        if ((tptr == NULL) || (*tptr != 0)) return SCPE_ARG;
        if ((pflag & A_REL) == 0)
            disp = (disp - ad32) & 0177777;
        if ((disp & 1) || ((disp > 2) && (disp < 0177604))) return SCPE_ARG;
        val[0] = val[0] | (((2 - disp) >> 1) & 077);
        break;

    case I_V_RSOP:                                      /* reg, sop */
        cptr = get_glyph (cptr, gbuf, ',');             /* get glyph */
        if ((reg = get_reg (gbuf, 0)) < 0) return SCPE_ARG;
        val[0] = val[0] | (reg << 6);                   /* fall through */
    case I_V_SOP:                                       /* sop */
        cptr = get_glyph (cptr, gbuf, 0);               /* get glyph */
        if ((n1 = get_spec (gbuf, ad32, 0, &spec, &val[1])) > 0)
            return SCPE_ARG;
        val[0] = val[0] | spec;
        break;

    case I_V_SOPR:                                      /* dop, reg */
        cptr = get_glyph (cptr, gbuf, ',');             /* get glyph */
        if ((n1 = get_spec (gbuf, ad32, 0, &spec, &val[1])) > 0)
            return SCPE_ARG;
        val[0] = val[0] | spec;
        cptr = get_glyph (cptr, gbuf, 0);               /* get glyph */
        if ((reg = get_reg (gbuf, 0)) < 0) return SCPE_ARG;
        val[0] = val[0] | (reg << 6);
        break;

    case I_V_DOP:                                       /* double op */
        cptr = get_glyph (cptr, gbuf, ',');             /* get glyph */
        if ((n1 = get_spec (gbuf, ad32, 0, &spec, &val[1])) > 0)
            return SCPE_ARG;
        val[0] = val[0] | (spec << 6);
        cptr = get_glyph (cptr, gbuf, 0);               /* get glyph */
        if ((n2 = get_spec (gbuf, ad32, n1, &spec, &val[1 - n1])) > 0)
             return SCPE_ARG;
        val[0] = val[0] | spec;
        break;

    case I_V_CCC: case I_V_CCS:                         /* cond code oper */
        for (cptr = get_glyph (cptr, gbuf, 0); gbuf[0] != 0;
            cptr = get_glyph (cptr, gbuf, 0)) {
            for (i = 0; (opcode[i] != NULL) &&
                (strcmp (opcode[i], gbuf) != 0) ; i++) ;
            if ((((opc_val[i] >> I_V_CL) & I_M_CL) != j) ||
                (opcode[i] == NULL)) return SCPE_ARG;
                val[0] = val[0] | (opc_val[i] & 0177777);
            }
        break;

    default:
        return SCPE_ARG;
        }

if (*cptr != 0) return SCPE_ARG;                        /* junk at end? */
for (i = j = 0; i < 3; i++, j = j + 2) {
    bytes[j] = val[i] & BMASK;
    bytes[j + 1] = (val[i] >> 8) & BMASK;
	}
return ((2 * (n1 + n2)) - 1);
}
