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% This file is part of the MMIXware package (c) Donald E Knuth 1999

@i boilerplate.w %<< legal stuff: PLEASE READ IT BEFORE MAKING ANY CHANGES!

\def\title{MMIX-IO}

\def\MMIX{\.{MMIX}}

\def\Hex#1{\hbox{$^{\scriptscriptstyle\#}$\tt#1}} % experimental hex constant

@*Introduction. This program module contains brute-force implementations

of the ten input/output primitives defined at the beginning of {\mc MMIX-SIM}.

The subroutines are grouped here as a separate package, because they

are intended to be loaded with the pipeline simulator as well as with the

simple simulator.

@^I/O@>

@^input/output@>

@c

@@;

@@;

@@;

@@;

@@;

@ Of course we include standard \CEE/ library routines, and we set things

up to accommodate older versions of \CEE/.

@=

#include 

#include 

#ifdef __STDC__

#define ARGS(list) list

#else

#define ARGS(list) ()

#endif

#ifndef FILENAME_MAX

#define FILENAME_MAX 256

#endif

#ifndef SEEK_SET

#define SEEK_SET 0

#endif

#ifndef SEEK_END

#define SEEK_END 2

#endif

@ The unsigned 32-bit type \&{tetra} must agree with its definition

in the simulators.

@=

typedef unsigned int tetra;

typedef struct {tetra h,l;} octa; /* two tetrabytes make one octabyte */

@ Three basic subroutines are used to get strings from the simulated

memory and to put strings into that memory. These subroutines are

defined appropriately in each simulator. We also use a few subroutines

and constants defined in {\mc MMIX-ARITH}.

@=

extern char stdin_chr @,@,@[ARGS((void))@];

extern int mmgetchars @,@,@[ARGS((char* buf,int size,octa addr,int stop))@];

extern void mmputchars @,@,@[ARGS((unsigned char* buf,int size,octa addr))@];

extern octa oplus @,@,@[ARGS((octa,octa))@];

extern octa ominus @,@,@[ARGS((octa,octa))@];

extern octa incr @,@,@[ARGS((octa,int))@];

extern octa zero_octa; /* |zero_octa.h=zero_octa.l=0| */

extern octa neg_one; /* |neg_one.h=neg_one.l=-1| */

@ Each possible handle has a file pointer and a current mode.

@=

typedef struct {

  FILE *fp; /* file pointer */

  int mode; /* [read OK] + 2[write OK] + 4[binary] + 8[readwrite] */

} sim_file_info;

@ @=

sim_file_info sfile[256];

@ The first three handles are initially open.

@=

void mmix_io_init @,@,@[ARGS((void))@];@+@t}\6{@>

void mmix_io_init()

{

  sfile[0].fp=stdin, sfile[0].mode=1;

  sfile[1].fp=stdout, sfile[1].mode=2;

  sfile[2].fp=stderr, sfile[2].mode=2;

}

@ The only tricky thing about these routines is that we want to

protect the standard input, output, and error streams from being

preempted.

@=

octa mmix_fopen @,@,@[ARGS((unsigned char,octa,octa))@];@+@t}\6{@>

octa mmix_fopen(handle,name,mode)

  unsigned char handle;

  octa name,mode;

{

  char name_buf[FILENAME_MAX];

  if (mode.h || mode.l>4) goto abort;

  if (mmgetchars(name_buf,FILENAME_MAX,name,0)==FILENAME_MAX) goto abort;

  if (sfile[handle].mode!=0 && handle>2) fclose(sfile[handle].fp);

  sfile[handle].fp=fopen(name_buf,mode_string[mode.l]);

  if (!sfile[handle].fp) goto abort;

  sfile[handle].mode=mode_code[mode.l];

  return zero_octa; /* success */

 abort: sfile[handle].mode=0;

  return neg_one; /* failure */

}

@ @=

char *mode_string[]={"r","w","rb","wb","w+b"};

int mode_code[]={0x1,0x2,0x5,0x6,0xf};

@ If the simulator is being used interactively, we can avoid competition

for |stdin| by substituting another file.

@=

void mmix_fake_stdin @,@,@[ARGS((FILE*))@];@+@t}\6{@>

void mmix_fake_stdin(f)

  FILE *f;

{

  sfile[0].fp=f; /* |f| should be open in mode \.{"r"} */

}

@ @=

octa mmix_fclose @,@,@[ARGS((unsigned char))@];@+@t}\6{@>

octa mmix_fclose(handle)

  unsigned char handle;

{

  if (sfile[handle].mode==0) return neg_one;

  if (handle>2 && fclose(sfile[handle].fp)!=0) return neg_one;

  sfile[handle].mode=0;

  return zero_octa; /* success */

}

@ @=

octa mmix_fread @,@,@[ARGS((unsigned char,octa,octa))@];@+@t}\6{@>

octa mmix_fread(handle,buffer,size)

  unsigned char handle;

  octa buffer,size;

{

  register unsigned char *buf;

  register int n;

  octa o;

  o=neg_one;

  if (!(sfile[handle].mode&0x1)) goto done;

  if (sfile[handle].mode&0x8) sfile[handle].mode &=~ 0x2;

  if (size.h) goto done;

  buf=(unsigned char*)calloc(size.l,sizeof(char));

  if (!buf) goto done;

  @;

  mmputchars(buf,n,buffer);

  free(buf);

  o.h=0, o.l=n;

done: return ominus(o,size);

}

@ @=

if (sfile[handle].fp==stdin) {

  register unsigned char *p;

  for (p=buf,n=size.l; p

} else {

  clearerr(sfile[handle].fp);

  n=fread(buf,1,size.l,sfile[handle].fp);

  if (ferror(sfile[handle].fp)) {

    free(buf);

    goto done;

  }

}

@ @=

octa mmix_fgets @,@,@[ARGS((unsigned char,octa,octa))@];@+@t}\6{@>

octa mmix_fgets(handle,buffer,size)

  unsigned char handle;

  octa buffer,size;

{

  char buf[256];

  register int n,s;

  register char *p;

  octa o;

  int eof=0;

  if (!(sfile[handle].mode&0x1)) return neg_one;

  if (!size.l && !size.h) return neg_one;

  if (sfile[handle].mode&0x8) sfile[handle].mode &=~ 0x2;

  size=incr(size,-1);

  o=zero_octa;

  while (1) {

    @;

    mmputchars(buf,n+1,buffer);

    o=incr(o,n);

    size=incr(size,-n);

    if ((n&&buf[n-1]=='\n') || (!size.l&&!size.h) || eof) return o;

    buffer=incr(buffer,n);

  }

}

@ @=

s=255;

if (size.l

if (sfile[handle].fp==stdin)

  for (p=buf,n=0;n

    *p=stdin_chr();

    n++;

    if (*p++=='\n') break;

  }

else {

  if (!fgets(buf,s+1,sfile[handle].fp)) return neg_one;

  eof=feof(sfile[handle].fp);

  for (p=buf,n=0;n

    if (!*p && eof) break;

    n++;

    if (*p++=='\n') break;

  }

}

*p='\0';

@ The routines that deal with wyde characters might need to be

changed on a system that is little-endian; the author wishes

good luck to whoever has to do this.

\MMIX\ is always big-endian, but external files

prepared on random operating systems might be backwards.

@^little-endian versus big-endian@>

@^big-endian versus little-endian@>

@^system dependencies@>

@=

octa mmix_fgetws @,@,@[ARGS((unsigned char,octa,octa))@];@+@t}\6{@>

octa mmix_fgetws(handle,buffer,size)

  unsigned char handle;

  octa buffer,size;

{

  char buf[256];

  register int n,s;

  register char *p;

  octa o;

  int eof;

  if (!(sfile[handle].mode&0x1)) return neg_one;

  if (!size.l && !size.h) return neg_one;

  if (sfile[handle].mode&0x8) sfile[handle].mode &=~ 0x2;

  buffer.l&=-2;

  size=incr(size,-1);

  o=zero_octa;

  while (1) {

    @;

    mmputchars(buf,2*n+2,buffer);

    o=incr(o,n);

    size=incr(size,-n);

    if ((n&&buf[2*n-1]=='\n'&&buf[2*n-2]==0) || (!size.l&&!size.h) || eof)

      return o;

    buffer=incr(buffer,2*n);

  }

}

@ @=

s=127;

if (size.l

if (sfile[handle].fp==stdin)

  for (p=buf,n=0;n

    *p++=stdin_chr();@+*p++=stdin_chr();

    n++;

    if (*(p-1)=='\n' && *(p-2)==0) break;

  }

else for (p=buf,n=0;n

  if (fread(p,1,2,sfile[handle].fp)!=2) {

    eof=feof(sfile[handle].fp);

    if (!eof) return neg_one;

    break;

  }

  n++,p+=2;

    if (*(p-1)=='\n' && *(p-2)==0) break;

}

*p=*(p+1)='\0';

@ @=

octa mmix_fwrite @,@,@[ARGS((unsigned char,octa,octa))@];@+@t}\6{@>

octa mmix_fwrite(handle,buffer,size)

  unsigned char handle;

  octa buffer,size;

{

  char buf[256];

  register int n;

  if (!(sfile[handle].mode&0x2)) return ominus(zero_octa,size);

  if (sfile[handle].mode&0x8) sfile[handle].mode &=~ 0x1;

  while (1) {

    if (size.h || size.l>=256) n=mmgetchars(buf,256,buffer,-1);

    else n=mmgetchars(buf,size.l,buffer,-1);

    size=incr(size,-n);

    if (fwrite(buf,1,n,sfile[handle].fp)!=n) return ominus(zero_octa,size);

    fflush(sfile[handle].fp);

    if (!size.l && !size.h) return zero_octa;

    buffer=incr(buffer,n);

  }

}

@ @=

octa mmix_fputs @,@,@[ARGS((unsigned char,octa))@];@+@t}\6{@>

octa mmix_fputs(handle,string)

  unsigned char handle;

  octa string;

{

  char buf[256];

  register int n;

  octa o;

  o=zero_octa;

  if (!(sfile[handle].mode&0x2)) return neg_one;

  if (sfile[handle].mode&0x8) sfile[handle].mode &=~ 0x1;

  while (1) {

    n=mmgetchars(buf,256,string,0);

    if (fwrite(buf,1,n,sfile[handle].fp)!=n) return neg_one;

    o=incr(o,n);

    if (n<256) {

      fflush(sfile[handle].fp);

      return o;

    }

    string=incr(string,n);

  }

}

@ @=

octa mmix_fputws @,@,@[ARGS((unsigned char,octa))@];@+@t}\6{@>

octa mmix_fputws(handle,string)

  unsigned char handle;

  octa string;

{

  char buf[256];

  register int n;

  octa o;

  o=zero_octa;

  if (!(sfile[handle].mode&0x2)) return neg_one;

  if (sfile[handle].mode&0x8) sfile[handle].mode &=~ 0x1;

  while (1) {

    n=mmgetchars(buf,256,string,1);

    if (fwrite(buf,1,n,sfile[handle].fp)!=n) return neg_one;

    o=incr(o,n>>1);

    if (n<256) {

      fflush(sfile[handle].fp);

      return o;

    }

    string=incr(string,n);

  }

}

@ @d sign_bit ((unsigned)0x80000000)

@=

octa mmix_fseek @,@,@[ARGS((unsigned char,octa))@];@+@t}\6{@>

octa mmix_fseek(handle,offset)

  unsigned char handle;

  octa offset;

{

  if (!(sfile[handle].mode&0x4)) return neg_one;

  if (sfile[handle].mode&0x8) sfile[handle].mode = 0xf;

  if (offset.h&sign_bit) {

    if (offset.h!=0xffffffff || !(offset.l&sign_bit)) return neg_one;

    if (fseek(sfile[handle].fp,(int)offset.l+1,SEEK_END)!=0) return neg_one;

  }@+else {

    if (offset.h || (offset.l&sign_bit)) return neg_one;

    if (fseek(sfile[handle].fp,(int)offset.l,SEEK_SET)!=0) return neg_one;

  }

  return zero_octa;

}

@ @=

octa mmix_ftell @,@,@[ARGS((unsigned char))@];@+@t}\6{@>

octa mmix_ftell(handle)

  unsigned char handle;

{

  register long x;

  octa o;

  if (!(sfile[handle].mode&0x4)) return neg_one;

  x=ftell(sfile[handle].fp);

  if (x<0) return neg_one;

  o.h=0, o.l=x;

  return o;

}

@ One last subroutine belongs here, just in case the user has

modified the standard error handle.

@=

void print_trip_warning @,@,@[ARGS((int,octa))@];@+@t}\6{@>

void print_trip_warning(n,loc)

  int n;

  octa loc;

{

  if (sfile[2].mode&0x2)

    fprintf(sfile[2].fp,"Warning: %s at location %08x%08x\n",

             trip_warning[n],loc.h,loc.l);

}

@ @=

char *trip_warning[]={

"TRIP",

"integer divide check",

"integer overflow",

"float-to-fix overflow",

"invalid floating point operation",

"floating point overflow",

"floating point underflow",

"floating point division by zero",

"floating point inexact"};

@* Index.