WebSVN – SvarDOS – Diff – /svarcom/trunk/command.c


/* This file is part of the SvarCOM project and is published under the terms
 * of the MIT license.
 *
 * Copyright (C) 2021 Mateusz Viste
 *
 * 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 THE
 * AUTHORS OR COPYRIGHT HOLDERS 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.
 */
 
/*
 * SvarCOM is a command-line interpreter.
 *
 * a little memory area is allocated as high as possible. it contains:
 *  - a signature (like XMS drivers do)
 *  - a routine for exec'ing programs
 *  - a "last command" buffer for input history
 *
 * when svarcom starts, it tries locating the routine in memory.
 *
 * if found:
 *   waits for user input and processes it. if execing something is required, set the "next exec" field in routine's memory and quit.
 *
 * if not found:
 *   installs it by creating a new PSP, set int 22 vector to the routine, set my "parent PSP" to the routine
 *   and quit.
 *
 * PSP structure
 * http://www.piclist.com/techref/dos/psps.htm
 *
 *
 *
 * === MCB ===
 *
 * each time that DOS allocates memory, it prefixes the allocated memory with
 * a 16-bytes structure called a "Memory Control Block" (MCB). This control
 * block has the following structure:
 *
 * Offset  Size     Description
 *   00h   byte     'M' =  non-last member of the MCB chain
 *                  'Z' = indicates last entry in MCB chain
 *                  other values cause "Memory Allocation Failure" on exit
 *   01h   word     PSP segment address of the owner (Process Id)
 *                  possible values:
 *                    0 = free
 *                    8 = Allocated by DOS before first user pgm loaded
 *                    other = Process Id/PSP segment address of owner
 *   03h  word      number of paragraphs related to this MCB (excluding MCB)
 *   05h  11 bytes  reserved
 *   10h  ...       start of actual allocated memory block
 */
 
#include <i86.h>
#include <dos.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
 
#include <process.h>
 
#include "cmd.h"
#include "env.h"
#include "helpers.h"
#include "redir.h"
#include "rmodinit.h"
#include "sayonara.h"
 
 
struct config {
  unsigned char flags; /* command.com flags, as defined in rmodinit.h */
  char *execcmd;
  unsigned short envsiz;
};
 
 
/* parses command line the hard way (directly from PSP) */
static void parse_argv(struct config *cfg) {
  unsigned short i;
  const unsigned char *cmdlinelen = (unsigned char *)0x80;
  char *cmdline = (char *)0x81;
 
  memset(cfg, 0, sizeof(*cfg));
 
  /* set a NULL terminator on cmdline */
  cmdline[*cmdlinelen] = 0;
 
  for (i = 0;;) {
 
    /* skip over any leading spaces */
    for (;; i++) {
      if (cmdline[i] == 0) return;
      if (cmdline[i] != ' ') break;
    }
 
    if (cmdline[i] != '/') {
      output("Invalid parameter: ");
      outputnl(cmdline + i);
      /* exit(1); */
    } else {
      i++;        /* skip the slash */
      switch (cmdline[i]) {
        case 'c': /* /C = execute command and quit */
        case 'C':
          cfg->flags |= FLAG_EXEC_AND_QUIT;
          /* FALLTHRU */
        case 'k': /* /K = execute command and keep running */
        case 'K':
          cfg->execcmd = cmdline + i + 1;
          return;
 
        case 'e': /* preset the initial size of the environment block */
        case 'E':
          i++;
          if (cmdline[i] == ':') i++; /* could be /E:size */
          atous(&(cfg->envsiz), cmdline + i);
          if (cfg->envsiz < 64) cfg->envsiz = 0;
          break;
 
        case 'p': /* permanent shell (can't exit) */
        case 'P':
          cfg->flags |= FLAG_PERMANENT;
          break;
 
        case '?':
          outputnl("Starts the SvarCOM command interpreter");
          outputnl("");
          outputnl("COMMAND /E:nnn [/[C|K] command]");
          outputnl("");
          outputnl("/E:nnn     Sets the environment size to nnn bytes");
          outputnl("/P         Makes the new command interpreter permanent (can't exit)");
          outputnl("/C         Executes the specified command and returns");
          outputnl("/K         Executes the specified command and continues running");
          exit(1);
          break;
 
        default:
          output("Invalid switch:");
          output(" ");
          outputnl(cmdline + i);
          exit(1);
          break;
      }
    }
 
    /* move to next argument or quit processing if end of cmdline */
    for (i++; (cmdline[i] != 0) && (cmdline[i] != ' ') && (cmdline[i] != '/'); i++);
 
  }
}
 
 
static void buildprompt(char *s, unsigned short envseg) {
  /* locate the prompt variable or use the default pattern */
  const char far *fmt = env_lookup_val(envseg, "PROMPT");
  if ((fmt == NULL) || (*fmt == 0)) fmt = "$p$g"; /* fallback to default if empty */
  /* build the prompt string based on pattern */
  for (; *fmt != 0; fmt++) {
    if (*fmt != '$') {
      *s = *fmt;
      s++;
      continue;
    }
    /* escape code ($P, etc) */
    fmt++;
    switch (*fmt) {
      case 'Q':  /* $Q = = (equal sign) */
      case 'q':
        *s = '=';
        s++;
        break;
      case '$':  /* $$ = $ (dollar sign) */
        *s = '$';
        s++;
        break;
      case 'T':  /* $t = current time */
      case 't':
        s += sprintf(s, "00:00"); /* TODO */
        break;
      case 'D':  /* $D = current date */
      case 'd':
        s += sprintf(s, "1985-07-29"); /* TODO */
        break;
      case 'P':  /* $P = current drive and path */
      case 'p':
        _asm {
          mov ah, 0x19    /* DOS 1+ - GET CURRENT DRIVE */
          int 0x21
          mov bx, s
          mov [bx], al  /* AL = drive (00 = A:, 01 = B:, etc */
        }
        *s += 'A';
        s++;
        *s = ':';
        s++;
        *s = '\\';
        s++;
        _asm {
          mov ah, 0x47    /* DOS 2+ - CWD - GET CURRENT DIRECTORY */
          xor dl,dl       /* DL = drive number (00h = default, 01h = A:, etc) */
          mov si, s       /* DS:SI -> 64-byte buffer for ASCIZ pathname */
          int 0x21
        }
        while (*s != 0) s++; /* move ptr forward to end of pathname */
        break;
      case 'V':  /* $V = DOS version number */
      case 'v':
        s += sprintf(s, "VER"); /* TODO */
        break;
      case 'N':  /* $N = current drive */
      case 'n':
        _asm {
          mov ah, 0x19    /* DOS 1+ - GET CURRENT DRIVE */
          int 0x21
          mov bx, s
          mov [bx], al  /* AL = drive (00 = A:, 01 = B:, etc */
        }
        *s += 'A';
        s++;
        break;
      case 'G':  /* $G = > (greater-than sign) */
      case 'g':
        *s = '>';
        s++;
        break;
      case 'L':  /* $L = < (less-than sign) */
      case 'l':
        *s = '<';
        s++;
        break;
      case 'B':  /* $B = | (pipe) */
      case 'b':
        *s = '|';
        s++;
        break;
      case 'H':  /* $H = backspace (erases previous character) */
      case 'h':
        *s = '\b';
        s++;
        break;
      case 'E':  /* $E = Escape code (ASCII 27) */
      case 'e':
        *s = 27;
        s++;
        break;
      case '_':  /* $_ = CR+LF */
        *s = '\r';
        s++;
        *s = '\n';
        s++;
        break;
    }
  }
  *s = '$';
}
 
 
static void run_as_external(const char far *cmdline) {
  char buff[256];
  char const *argvlist[256];
  int i, n;
  /* copy buffer to a near var (incl. trailing CR), insert a space before
     every slash to make sure arguments are well separated */
  n = 0;
  i = 0;
  for (;;) {
    if (cmdline[i] == '/') buff[n++] = ' ';
    buff[n++] = cmdline[i++];
    if (buff[n] == 0) break;
  }
 
  cmd_explode(buff, cmdline, argvlist);
 
  /* for (i = 0; argvlist[i] != NULL; i++) printf("arg #%d = '%s'\r\n", i, argvlist[i]); */
 
  /* must be an external command then. this call should never return, unless
   * the other program failed to be executed. */
  execvp(argvlist[0], argvlist);
}
 
 
static void set_comspec_to_self(unsigned short envseg) {
  unsigned short *psp_envseg = (void *)(0x2c); /* pointer to my env segment field in the PSP */
  char far *myenv = MK_FP(*psp_envseg, 0);
  unsigned short varcount;
  char buff[256] = "COMSPEC=";
  char *buffptr = buff + 8;
  /* who am i? look into my own environment, at the end of it should be my EXEPATH string */
  while (*myenv != 0) {
    /* consume a NULL-terminated string */
    while (*myenv != 0) myenv++;
    /* move to next string */
    myenv++;
  }
  /* get next word, if 1 then EXEPATH follows */
  myenv++;
  varcount = *myenv;
  myenv++;
  varcount |= (*myenv << 8);
  myenv++;
  if (varcount != 1) return; /* NO EXEPATH FOUND */
  while (*myenv != 0) {
    *buffptr = *myenv;
    buffptr++;
    myenv++;
  }
  *buffptr = 0;
  /* printf("EXEPATH: '%s'\r\n", buff); */
  env_setvar(envseg, buff);
}
 
 
/* wait for user input */
static void cmdline_getinput(unsigned short inpseg, unsigned short inpoff) {
  _asm {
    push ax
    push bx
    push cx
    push dx
    push ds
 
    /* is DOSKEY support present? (INT 2Fh, AX=4800h, returns non-zero in AL if present) */
    mov ax, 0x4800
    int 0x2f
    mov bl, al /* save doskey status in BL */
 
    /* set up buffered input to inpseg:inpoff */
    mov ax, inpseg
    push ax
    pop ds
    mov dx, inpoff
 
    /* execute either DOS input or DOSKEY */
    test bl, bl /* zf set if no DOSKEY present */
    jnz DOSKEY
 
    mov ah, 0x0a
    int 0x21
    jmp short DONE
 
    DOSKEY:
    mov ax, 0x4810
    int 0x2f
 
    DONE:
    /* terminate command with a CR/LF */
    mov ah, 0x02 /* display character in dl */
    mov dl, 0x0d
    int 0x21
    mov dl, 0x0a
    int 0x21
 
    pop ds
    pop dx
    pop cx
    pop bx
    pop ax
  }
}
 
 
int main(void) {
  static struct config cfg;
  static unsigned short rmod_seg;
  static unsigned short far *rmod_envseg;
  static unsigned short far *lastexitcode;
  static unsigned char BUFFER[4096];
  static struct rmod_props far *rmod;
 
  parse_argv(&cfg);
 
  rmod = rmod_find();
  if (rmod == NULL) {
    rmod = rmod_install(cfg.envsiz);
    if (rmod == NULL) {
      outputnl("ERROR: rmod_install() failed");
      return(1);
    }
    /* copy flags to rmod's storage */
    rmod->flags = cfg.flags;
/*    printf("rmod installed at seg 0x%04X\r\n", rmod_seg); */
  } else {
/*    printf("rmod found at seg 0x%04x\r\n", rmod_seg); */
  }
 
  rmod_seg = rmod->rmodseg;
  rmod_envseg = MK_FP(rmod_seg, RMOD_OFFSET_ENVSEG);
  lastexitcode = MK_FP(rmod_seg, RMOD_OFFSET_LEXITCODE);
 
  /* make COMPSEC point to myself */
  set_comspec_to_self(*rmod_envseg);
 
/*  {
    unsigned short envsiz;
    unsigned short far *sizptr = MK_FP(*rmod_envseg - 1, 3);
    envsiz = *sizptr;
    envsiz *= 16;
    printf("rmod_inpbuff at %04X:%04X, env_seg at %04X:0000 (env_size = %u bytes)\r\n", rmod_seg, RMOD_OFFSET_INPBUFF, *rmod_envseg, envsiz);
  }*/
 
  do {
    char far *cmdline = rmod->inputbuf + 2;
 
 
    /* (re)load translation strings if needed */
    nls_langreload(BUFFER, *rmod_envseg);
 
    /* skip user input if I have a command to exec (/C or /K) */
    if (cfg.execcmd != NULL) {
      cmdline = cfg.execcmd;
      cfg.execcmd = NULL;
      goto EXEC_CMDLINE;
    }
 
    if (rmod->echoflag != 0) outputnl(""); /* terminate the previous command with a CR/LF */
 
    SKIP_NEWLINE:
 
    /* print shell prompt (only if ECHO is enabled) */
    if (rmod->echoflag != 0) {
      char *promptptr = BUFFER;
      buildprompt(promptptr, *rmod_envseg);
      _asm {
        push ax
        push dx
        mov ah, 0x09
        mov dx, promptptr
        int 0x21
        pop dx
        pop ax
      }
    }
 
    /* revert input history terminator to \r */
    if (cmdline[-1] != 0) {
      cmdline[(unsigned short)(cmdline[-1])] = '\r';
    }
 
    /* wait for user command line */
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
    cmdline_getinput(FP_SEG(rmod->inputbuf), FP_OFF(rmod->inputbuf));
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
    /* if nothing entered, loop again (but without appending an extra CR/LF) */
    if (cmdline[-1] == 0) goto SKIP_NEWLINE;
 
    /* replace \r by a zero terminator */
    cmdline[(unsigned char)(cmdline[-1])] = 0;
 
    /* I jump here when I need to exec an initial command (/C or /K) */
    EXEC_CMDLINE:
 
    /* move pointer forward to skip over any leading spaces */
    while (*cmdline == ' ') cmdline++;
 
    /* update rmod's ptr to COMPSPEC so it is always up to date */
    rmod_updatecomspecptr(rmod_seg, *rmod_envseg);
 
    /* handle redirections (if any) */
    if (redir_parsecmd(cmdline, BUFFER) != 0) {
      outputnl("");
      continue;
    }
 
    /* try matching (and executing) an internal command */
    if (cmd_process(rmod, *rmod_envseg, cmdline, BUFFER) >= -1) {
      /* internal command executed */
      redir_revert(); /* revert stdout (in case it was redirected) */
      continue;
    }
 
    /* if here, then this was not an internal command */
    run_as_external(cmdline);
 
    /* revert stdout (in case it was redirected) */
    redir_revert();
 
    /* execvp() replaces the current process by the new one
    if I am still alive then external command failed to execute */
    outputnl("Bad command or file name");
 
  } while ((rmod->flags & FLAG_EXEC_AND_QUIT) == 0);
 
  sayonara(rmod);
  return(0);
}
 

Rev 449	Rev 450
1	`/* This file is part of the SvarCOM project and is published under the terms`	1	`/* This file is part of the SvarCOM project and is published under the terms`
2	`* of the MIT license.`	2	`* of the MIT license.`
3	`*`	3	`*`
4	`* Copyright (C) 2021 Mateusz Viste`	4	`* Copyright (C) 2021 Mateusz Viste`
5	`*`	5	`*`
6	`* Permission is hereby granted, free of charge, to any person obtaining a`	6	`* Permission is hereby granted, free of charge, to any person obtaining a`
7	`* copy of this software and associated documentation files (the "Software"),`	7	`* copy of this software and associated documentation files (the "Software"),`
8	`* to deal in the Software without restriction, including without limitation`	8	`* to deal in the Software without restriction, including without limitation`
9	`* the rights to use, copy, modify, merge, publish, distribute, sublicense,`	9	`* the rights to use, copy, modify, merge, publish, distribute, sublicense,`
10	`* and/or sell copies of the Software, and to permit persons to whom the`	10	`* and/or sell copies of the Software, and to permit persons to whom the`
11	`* Software is furnished to do so, subject to the following conditions:`	11	`* Software is furnished to do so, subject to the following conditions:`
12	`*`	12	`*`
13	`* The above copyright notice and this permission notice shall be included in`	13	`* The above copyright notice and this permission notice shall be included in`
14	`* all copies or substantial portions of the Software.`	14	`* all copies or substantial portions of the Software.`
15	`*`	15	`*`
16	`* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR`	16	`* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR`
17	`* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,`	17	`* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,`
18	`* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE`	18	`* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE`
19	`* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER`	19	`* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER`
20	`* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING`	20	`* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING`
21	`* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER`	21	`* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER`
22	`* DEALINGS IN THE SOFTWARE.`	22	`* DEALINGS IN THE SOFTWARE.`
23	`*/`	23	`*/`
24		24
25	`/*`	25	`/*`
26	`* SvarCOM is a command-line interpreter.`	26	`* SvarCOM is a command-line interpreter.`
27	`*`	27	`*`
28	`* a little memory area is allocated as high as possible. it contains:`	28	`* a little memory area is allocated as high as possible. it contains:`
29	`* - a signature (like XMS drivers do)`	29	`* - a signature (like XMS drivers do)`
30	`* - a routine for exec'ing programs`	30	`* - a routine for exec'ing programs`
31	`* - a "last command" buffer for input history`	31	`* - a "last command" buffer for input history`
32	`*`	32	`*`
33	`* when svarcom starts, it tries locating the routine in memory.`	33	`* when svarcom starts, it tries locating the routine in memory.`
34	`*`	34	`*`
35	`* if found:`	35	`* if found:`
36	`* waits for user input and processes it. if execing something is required, set the "next exec" field in routine's memory and quit.`	36	`* waits for user input and processes it. if execing something is required, set the "next exec" field in routine's memory and quit.`
37	`*`	37	`*`
38	`* if not found:`	38	`* if not found:`
39	`* installs it by creating a new PSP, set int 22 vector to the routine, set my "parent PSP" to the routine`	39	`* installs it by creating a new PSP, set int 22 vector to the routine, set my "parent PSP" to the routine`
40	`* and quit.`	40	`* and quit.`
41	`*`	41	`*`
42	`* PSP structure`	42	`* PSP structure`
43	`* http://www.piclist.com/techref/dos/psps.htm`	43	`* http://www.piclist.com/techref/dos/psps.htm`
44	`*`	44	`*`
45	`*`	45	`*`
46	`*`	46	`*`
47	`* === MCB ===`	47	`* === MCB ===`
48	`*`	48	`*`
49	`* each time that DOS allocates memory, it prefixes the allocated memory with`	49	`* each time that DOS allocates memory, it prefixes the allocated memory with`
50	`* a 16-bytes structure called a "Memory Control Block" (MCB). This control`	50	`* a 16-bytes structure called a "Memory Control Block" (MCB). This control`
51	`* block has the following structure:`	51	`* block has the following structure:`
52	`*`	52	`*`
53	`* Offset Size Description`	53	`* Offset Size Description`
54	`* 00h byte 'M' = non-last member of the MCB chain`	54	`* 00h byte 'M' = non-last member of the MCB chain`
55	`* 'Z' = indicates last entry in MCB chain`	55	`* 'Z' = indicates last entry in MCB chain`
56	`* other values cause "Memory Allocation Failure" on exit`	56	`* other values cause "Memory Allocation Failure" on exit`
57	`* 01h word PSP segment address of the owner (Process Id)`	57	`* 01h word PSP segment address of the owner (Process Id)`
58	`* possible values:`	58	`* possible values:`
59	`* 0 = free`	59	`* 0 = free`
60	`* 8 = Allocated by DOS before first user pgm loaded`	60	`* 8 = Allocated by DOS before first user pgm loaded`
61	`* other = Process Id/PSP segment address of owner`	61	`* other = Process Id/PSP segment address of owner`
62	`* 03h word number of paragraphs related to this MCB (excluding MCB)`	62	`* 03h word number of paragraphs related to this MCB (excluding MCB)`
63	`* 05h 11 bytes reserved`	63	`* 05h 11 bytes reserved`
64	`* 10h ... start of actual allocated memory block`	64	`* 10h ... start of actual allocated memory block`
65	`*/`	65	`*/`
66		66
67	`#include <i86.h>`	67	`#include <i86.h>`
68	`#include <dos.h>`	68	`#include <dos.h>`
69	`#include <stdio.h>`	69	`#include <stdio.h>`
70	`#include <stdlib.h>`	70	`#include <stdlib.h>`
71	`#include <string.h>`	71	`#include <string.h>`
72		72
73	`#include <process.h>`	73	`#include <process.h>`
74		74
75	`#include "cmd.h"`	75	`#include "cmd.h"`
76	`#include "env.h"`	76	`#include "env.h"`
77	`#include "helpers.h"`	77	`#include "helpers.h"`
78	`#include "redir.h"`	78	`#include "redir.h"`
79	`#include "rmodinit.h"`	79	`#include "rmodinit.h"`
80	`#include "sayonara.h"`	80	`#include "sayonara.h"`
81		81
82		82
83	`struct config {`	83	`struct config {`
84	`unsigned char flags; /* command.com flags, as defined in rmodinit.h */`	84	`unsigned char flags; /* command.com flags, as defined in rmodinit.h */`
85	`char *execcmd;`	85	`char *execcmd;`
86	`unsigned short envsiz;`	86	`unsigned short envsiz;`
87	`};`	87	`};`
88		88
89		89
90	`/* parses command line the hard way (directly from PSP) */`	90	`/* parses command line the hard way (directly from PSP) */`
91	`static void parse_argv(struct config *cfg) {`	91	`static void parse_argv(struct config *cfg) {`
92	`unsigned short i;`	92	`unsigned short i;`
93	`const unsigned char cmdlinelen = (unsigned char )0x80;`	93	`const unsigned char cmdlinelen = (unsigned char )0x80;`
94	`char cmdline = (char )0x81;`	94	`char cmdline = (char )0x81;`
95		95
96	`memset(cfg, 0, sizeof(*cfg));`	96	`memset(cfg, 0, sizeof(*cfg));`
97		97
98	`/* set a NULL terminator on cmdline */`	98	`/* set a NULL terminator on cmdline */`
99	`cmdline[*cmdlinelen] = 0;`	99	`cmdline[*cmdlinelen] = 0;`
100		100
101	`for (i = 0;;) {`	101	`for (i = 0;;) {`
102		102
103	`/* skip over any leading spaces */`	103	`/* skip over any leading spaces */`
104	`for (;; i++) {`	104	`for (;; i++) {`
105	`if (cmdline[i] == 0) return;`	105	`if (cmdline[i] == 0) return;`
106	`if (cmdline[i] != ' ') break;`	106	`if (cmdline[i] != ' ') break;`
107	`}`	107	`}`
108		108
109	`if (cmdline[i] != '/') {`	109	`if (cmdline[i] != '/') {`
110	`output("Invalid parameter: ");`	110	`output("Invalid parameter: ");`
111	`outputnl(cmdline + i);`	111	`outputnl(cmdline + i);`
112	`/* exit(1); */`	112	`/* exit(1); */`
113	`} else {`	113	`} else {`
114	`i++; /* skip the slash */`	114	`i++; /* skip the slash */`
115	`switch (cmdline[i]) {`	115	`switch (cmdline[i]) {`
116	`case 'c': /* /C = execute command and quit */`	116	`case 'c': /* /C = execute command and quit */`
117	`case 'C':`	117	`case 'C':`
118	`cfg->flags \|= FLAG_EXEC_AND_QUIT;`	118	`cfg->flags \|= FLAG_EXEC_AND_QUIT;`
119	`/* FALLTHRU */`	119	`/* FALLTHRU */`
120	`case 'k': /* /K = execute command and keep running */`	120	`case 'k': /* /K = execute command and keep running */`
121	`case 'K':`	121	`case 'K':`
122	`cfg->execcmd = cmdline + i + 1;`	122	`cfg->execcmd = cmdline + i + 1;`
123	`return;`	123	`return;`
124		124
125	`case 'e': /* preset the initial size of the environment block */`	125	`case 'e': /* preset the initial size of the environment block */`
126	`case 'E':`	126	`case 'E':`
127	`i++;`	127	`i++;`
128	`if (cmdline[i] == ':') i++; /* could be /E:size */`	128	`if (cmdline[i] == ':') i++; /* could be /E:size */`
129	`atous(&(cfg->envsiz), cmdline + i);`	129	`atous(&(cfg->envsiz), cmdline + i);`
130	`if (cfg->envsiz < 64) cfg->envsiz = 0;`	130	`if (cfg->envsiz < 64) cfg->envsiz = 0;`
131	`break;`	131	`break;`
132		132
133	`case 'p': /* permanent shell (can't exit) */`	133	`case 'p': /* permanent shell (can't exit) */`
134	`case 'P':`	134	`case 'P':`
135	`cfg->flags \|= FLAG_PERMANENT;`	135	`cfg->flags \|= FLAG_PERMANENT;`
136	`break;`	136	`break;`
137		137
138	`case '?':`	138	`case '?':`
139	`outputnl("Starts the SvarCOM command interpreter");`	139	`outputnl("Starts the SvarCOM command interpreter");`
140	`outputnl("");`	140	`outputnl("");`
141	`outputnl("COMMAND /E:nnn [/[C\|K] command]");`	141	`outputnl("COMMAND /E:nnn [/[C\|K] command]");`
142	`outputnl("");`	142	`outputnl("");`
143	`outputnl("/E:nnn Sets the environment size to nnn bytes");`	143	`outputnl("/E:nnn Sets the environment size to nnn bytes");`
144	`outputnl("/P Makes the new command interpreter permanent (can't exit)");`	144	`outputnl("/P Makes the new command interpreter permanent (can't exit)");`
145	`outputnl("/C Executes the specified command and returns");`	145	`outputnl("/C Executes the specified command and returns");`
146	`outputnl("/K Executes the specified command and continues running");`	146	`outputnl("/K Executes the specified command and continues running");`
147	`exit(1);`	147	`exit(1);`
148	`break;`	148	`break;`
149		149
150	`default:`	150	`default:`
151	`output("Invalid switch:");`	151	`output("Invalid switch:");`
152	`output(" ");`	152	`output(" ");`
153	`outputnl(cmdline + i);`	153	`outputnl(cmdline + i);`
154	`exit(1);`	154	`exit(1);`
155	`break;`	155	`break;`
156	`}`	156	`}`
157	`}`	157	`}`
158		158
159	`/* move to next argument or quit processing if end of cmdline */`	159	`/* move to next argument or quit processing if end of cmdline */`
160	`for (i++; (cmdline[i] != 0) && (cmdline[i] != ' ') && (cmdline[i] != '/'); i++);`	160	`for (i++; (cmdline[i] != 0) && (cmdline[i] != ' ') && (cmdline[i] != '/'); i++);`
161		161
162	`}`	162	`}`
163	`}`	163	`}`
164		164
165		165
166	`static void buildprompt(char *s, unsigned short envseg) {`	166	`static void buildprompt(char *s, unsigned short envseg) {`
167	`/* locate the prompt variable or use the default pattern */`	167	`/* locate the prompt variable or use the default pattern */`
168	`const char far *fmt = env_lookup_val(envseg, "PROMPT");`	168	`const char far *fmt = env_lookup_val(envseg, "PROMPT");`
169	`if ((fmt == NULL) \|\| (fmt == 0)) fmt = "$p$g"; / fallback to default if empty */`	169	`if ((fmt == NULL) \|\| (fmt == 0)) fmt = "$p$g"; / fallback to default if empty */`
170	`/* build the prompt string based on pattern */`	170	`/* build the prompt string based on pattern */`
171	`for (; *fmt != 0; fmt++) {`	171	`for (; *fmt != 0; fmt++) {`
172	`if (*fmt != '$') {`	172	`if (*fmt != '$') {`
173	`s = fmt;`	173	`s = fmt;`
174	`s++;`	174	`s++;`
175	`continue;`	175	`continue;`
176	`}`	176	`}`
177	`/* escape code ($P, etc) */`	177	`/* escape code ($P, etc) */`
178	`fmt++;`	178	`fmt++;`
179	`switch (*fmt) {`	179	`switch (*fmt) {`
180	`case 'Q': /* $Q = = (equal sign) */`	180	`case 'Q': /* $Q = = (equal sign) */`
181	`case 'q':`	181	`case 'q':`
182	`*s = '=';`	182	`*s = '=';`
183	`s++;`	183	`s++;`
184	`break;`	184	`break;`
185	`case '$': /* $$ = $ (dollar sign) */`	185	`case '$': /* $$ = $ (dollar sign) */`
186	`*s = '$';`	186	`*s = '$';`
187	`s++;`	187	`s++;`
188	`break;`	188	`break;`
189	`case 'T': /* $t = current time */`	189	`case 'T': /* $t = current time */`
190	`case 't':`	190	`case 't':`
191	`s += sprintf(s, "00:00"); /* TODO */`	191	`s += sprintf(s, "00:00"); /* TODO */`
192	`break;`	192	`break;`
193	`case 'D': /* $D = current date */`	193	`case 'D': /* $D = current date */`
194	`case 'd':`	194	`case 'd':`
195	`s += sprintf(s, "1985-07-29"); /* TODO */`	195	`s += sprintf(s, "1985-07-29"); /* TODO */`
196	`break;`	196	`break;`
197	`case 'P': /* $P = current drive and path */`	197	`case 'P': /* $P = current drive and path */`
198	`case 'p':`	198	`case 'p':`
199	`_asm {`	199	`_asm {`
200	`mov ah, 0x19 /* DOS 1+ - GET CURRENT DRIVE */`	200	`mov ah, 0x19 /* DOS 1+ - GET CURRENT DRIVE */`
201	`int 0x21`	201	`int 0x21`
202	`mov bx, s`	202	`mov bx, s`
203	`mov [bx], al /* AL = drive (00 = A:, 01 = B:, etc */`	203	`mov [bx], al /* AL = drive (00 = A:, 01 = B:, etc */`
204	`}`	204	`}`
205	`*s += 'A';`	205	`*s += 'A';`
206	`s++;`	206	`s++;`
207	`*s = ':';`	207	`*s = ':';`
208	`s++;`	208	`s++;`
209	`*s = '\\';`	209	`*s = '\\';`
210	`s++;`	210	`s++;`
211	`_asm {`	211	`_asm {`
212	`mov ah, 0x47 /* DOS 2+ - CWD - GET CURRENT DIRECTORY */`	212	`mov ah, 0x47 /* DOS 2+ - CWD - GET CURRENT DIRECTORY */`
213	`xor dl,dl /* DL = drive number (00h = default, 01h = A:, etc) */`	213	`xor dl,dl /* DL = drive number (00h = default, 01h = A:, etc) */`
214	`mov si, s /* DS:SI -> 64-byte buffer for ASCIZ pathname */`	214	`mov si, s /* DS:SI -> 64-byte buffer for ASCIZ pathname */`
215	`int 0x21`	215	`int 0x21`
216	`}`	216	`}`
217	`while (s != 0) s++; / move ptr forward to end of pathname */`	217	`while (s != 0) s++; / move ptr forward to end of pathname */`
218	`break;`	218	`break;`
219	`case 'V': /* $V = DOS version number */`	219	`case 'V': /* $V = DOS version number */`
220	`case 'v':`	220	`case 'v':`
221	`s += sprintf(s, "VER"); /* TODO */`	221	`s += sprintf(s, "VER"); /* TODO */`
222	`break;`	222	`break;`
223	`case 'N': /* $N = current drive */`	223	`case 'N': /* $N = current drive */`
224	`case 'n':`	224	`case 'n':`
225	`_asm {`	225	`_asm {`
226	`mov ah, 0x19 /* DOS 1+ - GET CURRENT DRIVE */`	226	`mov ah, 0x19 /* DOS 1+ - GET CURRENT DRIVE */`
227	`int 0x21`	227	`int 0x21`
228	`mov bx, s`	228	`mov bx, s`
229	`mov [bx], al /* AL = drive (00 = A:, 01 = B:, etc */`	229	`mov [bx], al /* AL = drive (00 = A:, 01 = B:, etc */`
230	`}`	230	`}`
231	`*s += 'A';`	231	`*s += 'A';`
232	`s++;`	232	`s++;`
233	`break;`	233	`break;`
234	`case 'G': /* $G = > (greater-than sign) */`	234	`case 'G': /* $G = > (greater-than sign) */`
235	`case 'g':`	235	`case 'g':`
236	`*s = '>';`	236	`*s = '>';`
237	`s++;`	237	`s++;`
238	`break;`	238	`break;`
239	`case 'L': /* $L = < (less-than sign) */`	239	`case 'L': /* $L = < (less-than sign) */`
240	`case 'l':`	240	`case 'l':`
241	`*s = '<';`	241	`*s = '<';`
242	`s++;`	242	`s++;`
243	`break;`	243	`break;`
244	`case 'B': /* $B = \| (pipe) */`	244	`case 'B': /* $B = \| (pipe) */`
245	`case 'b':`	245	`case 'b':`
246	`*s = '\|';`	246	`*s = '\|';`
247	`s++;`	247	`s++;`
248	`break;`	248	`break;`
249	`case 'H': /* $H = backspace (erases previous character) */`	249	`case 'H': /* $H = backspace (erases previous character) */`
250	`case 'h':`	250	`case 'h':`
251	`*s = '\b';`	251	`*s = '\b';`
252	`s++;`	252	`s++;`
253	`break;`	253	`break;`
254	`case 'E': /* $E = Escape code (ASCII 27) */`	254	`case 'E': /* $E = Escape code (ASCII 27) */`
255	`case 'e':`	255	`case 'e':`
256	`*s = 27;`	256	`*s = 27;`
257	`s++;`	257	`s++;`
258	`break;`	258	`break;`
259	`case '_': /* $_ = CR+LF */`	259	`case '_': /* $_ = CR+LF */`
260	`*s = '\r';`	260	`*s = '\r';`
261	`s++;`	261	`s++;`
262	`*s = '\n';`	262	`*s = '\n';`
263	`s++;`	263	`s++;`
264	`break;`	264	`break;`
265	`}`	265	`}`
266	`}`	266	`}`
267	`*s = '$';`	267	`*s = '$';`
268	`}`	268	`}`
269		269
270		270
271	`static void run_as_external(const char far *cmdline) {`	271	`static void run_as_external(const char far *cmdline) {`
272	`char buff[256];`	272	`char buff[256];`
273	`char const *argvlist[256];`	273	`char const *argvlist[256];`
274	`int i, n;`	274	`int i, n;`
275	`/* copy buffer to a near var (incl. trailing CR), insert a space before`	275	`/* copy buffer to a near var (incl. trailing CR), insert a space before`
276	`every slash to make sure arguments are well separated */`	276	`every slash to make sure arguments are well separated */`
277	`n = 0;`	277	`n = 0;`
278	`i = 0;`	278	`i = 0;`
279	`for (;;) {`	279	`for (;;) {`
280	`if (cmdline[i] == '/') buff[n++] = ' ';`	280	`if (cmdline[i] == '/') buff[n++] = ' ';`
281	`buff[n++] = cmdline[i++];`	281	`buff[n++] = cmdline[i++];`
282	`if (buff[n] == 0) break;`	282	`if (buff[n] == 0) break;`
283	`}`	283	`}`
284		284
285	`cmd_explode(buff, cmdline, argvlist);`	285	`cmd_explode(buff, cmdline, argvlist);`
286		286
287	`/* for (i = 0; argvlist[i] != NULL; i++) printf("arg #%d = '%s'\r\n", i, argvlist[i]); */`	287	`/* for (i = 0; argvlist[i] != NULL; i++) printf("arg #%d = '%s'\r\n", i, argvlist[i]); */`
288		288
289	`/* must be an external command then. this call should never return, unless`	289	`/* must be an external command then. this call should never return, unless`
290	`* the other program failed to be executed. */`	290	`* the other program failed to be executed. */`
291	`execvp(argvlist[0], argvlist);`	291	`execvp(argvlist[0], argvlist);`
292	`}`	292	`}`
293		293
294		294
295	`static void set_comspec_to_self(unsigned short envseg) {`	295	`static void set_comspec_to_self(unsigned short envseg) {`
296	`unsigned short psp_envseg = (void )(0x2c); /* pointer to my env segment field in the PSP */`	296	`unsigned short psp_envseg = (void )(0x2c); /* pointer to my env segment field in the PSP */`
297	`char far myenv = MK_FP(psp_envseg, 0);`	297	`char far myenv = MK_FP(psp_envseg, 0);`
298	`unsigned short varcount;`	298	`unsigned short varcount;`
299	`char buff[256] = "COMSPEC=";`	299	`char buff[256] = "COMSPEC=";`
300	`char *buffptr = buff + 8;`	300	`char *buffptr = buff + 8;`
301	`/* who am i? look into my own environment, at the end of it should be my EXEPATH string */`	301	`/* who am i? look into my own environment, at the end of it should be my EXEPATH string */`
302	`while (*myenv != 0) {`	302	`while (*myenv != 0) {`
303	`/* consume a NULL-terminated string */`	303	`/* consume a NULL-terminated string */`
304	`while (*myenv != 0) myenv++;`	304	`while (*myenv != 0) myenv++;`
305	`/* move to next string */`	305	`/* move to next string */`
306	`myenv++;`	306	`myenv++;`
307	`}`	307	`}`
308	`/* get next word, if 1 then EXEPATH follows */`	308	`/* get next word, if 1 then EXEPATH follows */`
309	`myenv++;`	309	`myenv++;`
310	`varcount = *myenv;`	310	`varcount = *myenv;`
311	`myenv++;`	311	`myenv++;`
312	`varcount \|= (*myenv << 8);`	312	`varcount \|= (*myenv << 8);`
313	`myenv++;`	313	`myenv++;`
314	`if (varcount != 1) return; /* NO EXEPATH FOUND */`	314	`if (varcount != 1) return; /* NO EXEPATH FOUND */`
315	`while (*myenv != 0) {`	315	`while (*myenv != 0) {`
316	`buffptr = myenv;`	316	`buffptr = myenv;`
317	`buffptr++;`	317	`buffptr++;`
318	`myenv++;`	318	`myenv++;`
319	`}`	319	`}`
320	`*buffptr = 0;`	320	`*buffptr = 0;`
321	`/* printf("EXEPATH: '%s'\r\n", buff); */`	321	`/* printf("EXEPATH: '%s'\r\n", buff); */`
322	`env_setvar(envseg, buff);`	322	`env_setvar(envseg, buff);`
323	`}`	323	`}`
324		324
325		325
-		326	`/* wait for user input */`
-		327	`static void cmdline_getinput(unsigned short inpseg, unsigned short inpoff) {`
-		328	`_asm {`
-		329	`push ax`
-		330	`push bx`
-		331	`push cx`
-		332	`push dx`
-		333	`push ds`
-		334
-		335	`/* is DOSKEY support present? (INT 2Fh, AX=4800h, returns non-zero in AL if present) */`
-		336	`mov ax, 0x4800`
-		337	`int 0x2f`
-		338	`mov bl, al /* save doskey status in BL */`
-		339
-		340	`/* set up buffered input to inpseg:inpoff */`
-		341	`mov ax, inpseg`
-		342	`push ax`
-		343	`pop ds`
-		344	`mov dx, inpoff`
-		345
-		346	`/* execute either DOS input or DOSKEY */`
-		347	`test bl, bl /* zf set if no DOSKEY present */`
-		348	`jnz DOSKEY`
-		349
-		350	`mov ah, 0x0a`
-		351	`int 0x21`
-		352	`jmp short DONE`
-		353
-		354	`DOSKEY:`
-		355	`mov ax, 0x4810`
-		356	`int 0x2f`
-		357
-		358	`DONE:`
-		359	`/* terminate command with a CR/LF */`
-		360	`mov ah, 0x02 /* display character in dl */`
-		361	`mov dl, 0x0d`
-		362	`int 0x21`
-		363	`mov dl, 0x0a`
-		364	`int 0x21`
-		365
-		366	`pop ds`
-		367	`pop dx`
-		368	`pop cx`
-		369	`pop bx`
-		370	`pop ax`
-		371	`}`
-		372	`}`
-		373
-		374
326	`int main(void) {`	375	`int main(void) {`
327	`static struct config cfg;`	376	`static struct config cfg;`
328	`static unsigned short rmod_seg;`	377	`static unsigned short rmod_seg;`
329	`static unsigned short far *rmod_envseg;`	378	`static unsigned short far *rmod_envseg;`
330	`static unsigned short far *lastexitcode;`	379	`static unsigned short far *lastexitcode;`
331	`static unsigned char BUFFER[4096];`	380	`static unsigned char BUFFER[4096];`
332	`static struct rmod_props far *rmod;`	381	`static struct rmod_props far *rmod;`
333		382
334	`parse_argv(&cfg);`	383	`parse_argv(&cfg);`
335		384
336	`rmod = rmod_find();`	385	`rmod = rmod_find();`
337	`if (rmod == NULL) {`	386	`if (rmod == NULL) {`
338	`rmod = rmod_install(cfg.envsiz);`	387	`rmod = rmod_install(cfg.envsiz);`
339	`if (rmod == NULL) {`	388	`if (rmod == NULL) {`
340	`outputnl("ERROR: rmod_install() failed");`	389	`outputnl("ERROR: rmod_install() failed");`
341	`return(1);`	390	`return(1);`
342	`}`	391	`}`
343	`/* copy flags to rmod's storage */`	392	`/* copy flags to rmod's storage */`
344	`rmod->flags = cfg.flags;`	393	`rmod->flags = cfg.flags;`
345	`/* printf("rmod installed at seg 0x%04X\r\n", rmod_seg); */`	394	`/* printf("rmod installed at seg 0x%04X\r\n", rmod_seg); */`
346	`} else {`	395	`} else {`
347	`/* printf("rmod found at seg 0x%04x\r\n", rmod_seg); */`	396	`/* printf("rmod found at seg 0x%04x\r\n", rmod_seg); */`
348	`}`	397	`}`
349		398
350	`rmod_seg = rmod->rmodseg;`	399	`rmod_seg = rmod->rmodseg;`
351	`rmod_envseg = MK_FP(rmod_seg, RMOD_OFFSET_ENVSEG);`	400	`rmod_envseg = MK_FP(rmod_seg, RMOD_OFFSET_ENVSEG);`
352	`lastexitcode = MK_FP(rmod_seg, RMOD_OFFSET_LEXITCODE);`	401	`lastexitcode = MK_FP(rmod_seg, RMOD_OFFSET_LEXITCODE);`
353		402
354	`/* make COMPSEC point to myself */`	403	`/* make COMPSEC point to myself */`
355	`set_comspec_to_self(*rmod_envseg);`	404	`set_comspec_to_self(*rmod_envseg);`
356		405
357	`/* {`	406	`/* {`
358	`unsigned short envsiz;`	407	`unsigned short envsiz;`
359	`unsigned short far sizptr = MK_FP(rmod_envseg - 1, 3);`	408	`unsigned short far sizptr = MK_FP(rmod_envseg - 1, 3);`
360	`envsiz = *sizptr;`	409	`envsiz = *sizptr;`
361	`envsiz *= 16;`	410	`envsiz *= 16;`
362	`printf("rmod_inpbuff at %04X:%04X, env_seg at %04X:0000 (env_size = %u bytes)\r\n", rmod_seg, RMOD_OFFSET_INPBUFF, *rmod_envseg, envsiz);`	411	`printf("rmod_inpbuff at %04X:%04X, env_seg at %04X:0000 (env_size = %u bytes)\r\n", rmod_seg, RMOD_OFFSET_INPBUFF, *rmod_envseg, envsiz);`
363	`}*/`	412	`}*/`
364		413
365	`do {`	414	`do {`
366	`char far *cmdline = MK_FP(rmod_seg, RMOD_OFFSET_INPBUFF + 2);`	415	`char far *cmdline = rmod->inputbuf + 2;`
367	`unsigned char far *echostatus = MK_FP(rmod_seg, RMOD_OFFSET_ECHOFLAG);`	-
368		416
369	`/* (re)load translation strings if needed */`	417	`/* (re)load translation strings if needed */`
370	`nls_langreload(BUFFER, *rmod_envseg);`	418	`nls_langreload(BUFFER, *rmod_envseg);`
371		419
372	`/* skip user input if I have a command to exec (/C or /K) */`	420	`/* skip user input if I have a command to exec (/C or /K) */`
373	`if (cfg.execcmd != NULL) {`	421	`if (cfg.execcmd != NULL) {`
374	`cmdline = cfg.execcmd;`	422	`cmdline = cfg.execcmd;`
375	`cfg.execcmd = NULL;`	423	`cfg.execcmd = NULL;`
376	`goto EXEC_CMDLINE;`	424	`goto EXEC_CMDLINE;`
377	`}`	425	`}`
378		426
379	`if (echostatus != 0) outputnl(""); / terminate the previous command with a CR/LF */`	427	`if (rmod->echoflag != 0) outputnl(""); /* terminate the previous command with a CR/LF */`
380		428
381	`SKIP_NEWLINE:`	429	`SKIP_NEWLINE:`
382		430
383	`/* print shell prompt (only if ECHO is enabled) */`	431	`/* print shell prompt (only if ECHO is enabled) */`
384	`if (*echostatus != 0) {`	432	`if (rmod->echoflag != 0) {`
385	`char *promptptr = BUFFER;`	433	`char *promptptr = BUFFER;`
386	`buildprompt(promptptr, *rmod_envseg);`	434	`buildprompt(promptptr, *rmod_envseg);`
387	`_asm {`	435	`_asm {`
388	`push ax`	436	`push ax`
389	`push dx`	437	`push dx`
390	`mov ah, 0x09`	438	`mov ah, 0x09`
391	`mov dx, promptptr`	439	`mov dx, promptptr`
392	`int 0x21`	440	`int 0x21`
393	`pop dx`	441	`pop dx`
394	`pop ax`	442	`pop ax`
395	`}`	443	`}`
396	`}`	444	`}`
397		445
398	`/* revert input history terminator to \r */`	446	`/* revert input history terminator to \r */`
399	`if (cmdline[-1] != 0) {`	447	`if (cmdline[-1] != 0) {`
400	`cmdline[(unsigned short)(cmdline[-1])] = '\r';`	448	`cmdline[(unsigned short)(cmdline[-1])] = '\r';`
401	`}`	449	`}`
402		450
403	`/* wait for user input */`	451	`/* wait for user command line */`
404	`_asm {`	-
405	`push ax`	-
406	`push bx`	-
407	`push cx`	-
408	`push dx`	-
409	`push ds`	-
410		-
411	`/* is DOSKEY support present? (INT 2Fh, AX=4800h, returns non-zero in AL if present) */`	-
412	`mov ax, 0x4800`	-
413	`int 0x2f`	-
414	`mov bl, al /* save doskey status in BL */`	-
415		-
416	`/* set up buffered input */`	-
417	`mov ax, rmod_seg`	-
418	`push ax`	-
419	`pop ds`	-
420	`mov dx, RMOD_OFFSET_INPBUFF`	-
421		-
422	`/* execute either DOS input or DOSKEY */`	452	`cmdline_getinput(FP_SEG(rmod->inputbuf), FP_OFF(rmod->inputbuf));`
423	`test bl, bl /* zf set if no DOSKEY present */`	-
424	`jnz DOSKEY`	-
425		-
426	`mov ah, 0x0a`	-
427	`int 0x21`	-
428	`jmp short DONE`	-
429		-
430	`DOSKEY:`	-
431	`mov ax, 0x4810`	-
432	`int 0x2f`	-
433		-
434	`DONE:`	-
435	`/* terminate command with a CR/LF */`	-
436	`mov ah, 0x02 /* display character in dl */`	-
437	`mov dl, 0x0d`	-
438	`int 0x21`	-
439	`mov dl, 0x0a`	-
440	`int 0x21`	-
441		-
442	`pop ds`	-
443	`pop dx`	-
444	`pop cx`	-
445	`pop bx`	-
446	`pop ax`	-
447	`}`	-
448		453
449	`/* if nothing entered, loop again (but without appending an extra CR/LF) */`	454	`/* if nothing entered, loop again (but without appending an extra CR/LF) */`
450	`if (cmdline[-1] == 0) goto SKIP_NEWLINE;`	455	`if (cmdline[-1] == 0) goto SKIP_NEWLINE;`
451		456

Subversion Repositories SvarDOS

(root)/svarcom/trunk/command.c @ 1202 – Rev 449 → 450