138
MMIX-IO
1. Introduction. This program module contains brute-force implementations of
the ten input/output primitives de�ned at the beginning of MMIX-SIM. The subrou-
tines 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.
hPreprocessor macros 2 i
hType de�nitions 3 i
hExternal subroutines 4 i
hGlobal variables 6 i
h Subroutines 7 i
2. Of course we include standard C library routines, and we set things up to
accommodate older versions of C.
hPreprocessor macros 2 i �
#include
#include
#ifdef __STDC__
#de�ne ARGS(list ) list
#else
#de�ne ARGS(list ) ( )
#endif
#ifndef FILENAME_MAX
#de�ne FILENAME_MAX 256
#endif
#ifndef SEEK_SET
#de�ne SEEK_SET 0
#endif
#ifndef SEEK_END
#de�ne SEEK_END 2
#endif
This code is used in section 1.
3. The unsigned 32-bit type tetra must agree with its de�nition in the simulators.
hType de�nitions 3 i �
typedef unsigned int tetra;
typedef struct f
tetra h; l;
g octa; =� two tetrabytes makes one octabyte �=
See also section 5.
This code is used in section 1.
4. Three basic subroutines are used to get strings from the simulated memory and
to put strings into that memory. These subroutines are de�ned appropriately in each
simulator. We also use a few subroutines and constants de�ned in MMIX-ARITH.
hExternal subroutines 4 i �
extern char stdin chr ARGS((void));
extern int mmgetchars ARGS((char �buf ; int size ;octa addr ; int stop ));
D.E. Knuth: MMIXware, LNCS 1750, pp. 138-147, 1999.
Springer-Verlag Berlin Heidelberg 1999
139 MMIX-IO: INTRODUCTION
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 �=
This code is used in section 1.
5. Each possible handle has a �le pointer and a current mode.
hType de�nitions 3 i +�
typedef struct f
FILE �fp ; =� �le pointer �=
int mode ; =� [read OK] + 2[write OK] + 4[binary] + 8[readwrite] �=
g sim �le info;
6. hGlobal variables 6 i �
sim �le info s�le [256];
See also sections 9 and 24.
This code is used in section 1.
7. The �rst three handles are initially open.
hSubroutines 7 i �
void mmix io init ARGS((void));
void mmix io init ( )
f
s�le [0]:fp = stdin ; s�le [0]:mode = 1;
s�le [1]:fp = stdout ; s�le [1]:mode = 2;
s�le [2]:fp = stderr ; s�le [2]:mode = 2;
g
See also sections 8, 10, 11, 12, 14, 16, 18, 19, 20, 21, 22, and 23.
This code is used in section 1.
__STDC__, Standard C.
FILE, .
FILENAME_MAX=macro,
.
incr : octa ( ), MMIX-ARITH x6.
mmgetchars : int ( ),
MMIX-SIM x114.
mmgetchars : int ( ),
MMIX-PIPE x381.
mmputchars : int ( ),
MMIX-SIM x117.
mmputchars : int ( ),
MMIX-PIPE x384.
neg one : octa, MMIX-ARITH x4.
ominus : octa ( ),
MMIX-ARITH x5.
oplus : octa ( ), MMIX-ARITH x5.
SEEK_END=macro, .
SEEK_SET=macro, .
stderr : FILE �, .
stdin : FILE �, .
stdin chr : char ( ),
MMIX-SIM x120.
stdin chr : char ( ),
MMIX-PIPE x387.
stdout : FILE �, .
zero octa : octa,
MMIX-ARITH x4.
MMIX-IO: INTRODUCTION 140
8. The only tricky thing about these routines is that we want to protect the standard
input, output, and error streams from being preempted.
hSubroutines 7 i +�
octa mmix fopen ARGS((unsigned char;octa;octa));
octa mmix fopen (handle ; name ;mode )
unsigned char handle ;
octa name ; mode ;
f
char name buf [FILENAME_MAX];
FILE �tmp ;
if (mode :h _mode :l > 4) goto abort ;
if (mmgetchars (name buf ; FILENAME_MAX;name ; 0) � FILENAME_MAX) goto abort ;
if (s�le [handle ]:mode 6= 0 ^ handle > 2) fclose (s�le [handle ]:fp);
s�le [handle ]:fp = fopen (name buf ;mode string [mode :l]);
if (:s�le [handle ]:fp) goto abort ;
s�le [handle ]:mode = mode code [mode :l];
return zero octa ; =� success �=
abort : s�le [handle ]:mode = 0;
return neg one ; =� failure �=
g
9. hGlobal variables 6 i +�
char �mode string [ ] = f"r"; "w"; "rb"; "wb"; "w+b"g;
int mode code [ ] = f
#
1;
#
2;
#
5;
#
6;
#
fg;
10. If the simulator is being used interactively, we can avoid competition for stdin
by substituting another �le.
hSubroutines 7 i +�
void mmix fake stdin ARGS((FILE �));
void mmix fake stdin (f)
FILE �f ;
f
s�le [0]:fp = f ; =� f should be open in mode "r" �=
g
11. h Subroutines 7 i +�
octa mmix fclose ARGS((unsigned char));
octa mmix fclose (handle )
unsigned char handle ;
f
if (s�le [handle ]:mode � 0) return neg one ;
if (handle > 2 ^ fclose (s�le [handle ]:fp) 6= 0) return neg one ;
s�le [handle ]:mode = 0;
return zero octa ; =� success �=
g
141 MMIX-IO: INTRODUCTION
12. h Subroutines 7 i +�
octa mmix fread ARGS((unsigned char;octa;octa));
octa mmix fread (handle ; bu�er ; size )
unsigned char handle ;
octa bu�er ; size ;
f
register unsigned char �buf ;
register int n;
octa o;
o = neg one ;
if (:(s�le [handle ]:mode &
#
1)) goto done ;
if (s�le [handle ]:mode &
#
8) s�le [handle ]:mode &= �
#
2;
if (size :h) goto done ;
buf = (unsigned char �) calloc(size :l; sizeof (char));
if (:buf ) goto done ;
hRead n � size :l characters into buf 13 i;
mmputchars (buf ; n; bu�er );
free (buf );
o:h = 0; o:l = n;
done : return ominus (o; size );
g
13. hRead n � size :l characters into buf 13 i �
if (s�le [handle ]:fp � stdin ) f
register unsigned char �p;
for (p = buf ; n = size :l; p < buf + n; p
++
) �p = stdin chr ( );
g
else f
clearerr (s�le [handle ]:fp);
n = fread (buf ; 1; size :l; s�le [handle ]:fp);
if (ferror (s�le [handle ]:fp)) goto done ;
g
This code is used in section 12.
ARGS=macro ( ), x2.
calloc : void �( ), .
clearerr : void ( ), .
fclose : int ( ), .
ferror : int ( ), .
FILE, .
FILENAME_MAX=macro,
.
fopen : FILE �( ), .
fp : FILE �, x5.
fread : size t ( ), .
free : void ( ), .
h: tetra, x3.
l: tetra, x3.
mmgetchars : extern int ( ),
x4.
mmputchars : extern int ( ),
x4.
mode : int, x5.
neg one : octa, MMIX-ARITH x4.
octa= struct, x3.
ominus : octa ( ),
MMIX-ARITH x5.
s�le : sim �le info [ ], x6.
stdin : FILE �, .
stdin chr : extern char ( ), x4.
zero octa : octa,
MMIX-ARITH x4.
MMIX-IO: INTRODUCTION 142
14. h Subroutines 7 i +�
octa mmix fgets ARGS((unsigned char;octa;octa));
octa mmix fgets (handle ; bu�er ; size )
unsigned char handle ;
octa bu�er ; size ;
f
char buf [256];
register int n; s;
register char �p;
octa o;
int eof = 0;
if (:(s�le [handle ]:mode &
#
1)) return neg one ;
if (:size :l ^ :size :h) return neg one ;
if (s�le [handle ]:mode &
#
8) s�le [handle ]:mode &= �
#
2;
size = incr (size ;�1);
o = zero octa ;
while (1) f
hRead n < 256 characters into buf 15 i;
mmputchars (buf ; n+ 1; bu�er );
o = incr (o; n);
size = incr (size ;�n);
if ((n ^ buf [n� 1] � '\n') _ (:size :l ^ :size :h) _ eof ) return o;
bu�er = incr (bu�er ; n);
g
g
15. hRead n < 256 characters into buf 15 i �
s = 255;
if (size :l < s ^ :size :h) s = size :l;
if (s�le [handle ]:fp � stdin )
for (p = buf ; n = 0; n < s; ) f
�p = stdin chr ( );
n
++
;
if (�p
++
� '\n') break;
g
else f
if (:fgets (buf ; s+ 1; s�le [handle ]:fp )) return neg one ;
eof = feof (s�le [handle ]:fp);
for (p = buf ; n = 0; n < s; ) f
if (:�p ^ eof ) break;
n
++
;
if (�p
++
� '\n') break;
g
g
�p = '\0';
This code is used in section 14.
143 MMIX-IO: INTRODUCTION
16. 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 �les prepared on random operating systems
might be backwards.
hSubroutines 7 i +�
octa mmix fgetws ARGS((unsigned char;octa;octa));
octa mmix fgetws (handle ; bu�er ; size )
unsigned char handle ;
octa bu�er ; size ;
f
char buf [256];
register int n; s;
register char �p;
octa o;
int eof ;
if (:(s�le [handle ]:mode &
#
1)) return neg one ;
if (:size :l ^ :size :h) return neg one ;
if (s�le [handle ]:mode &
#
8) s�le [handle ]:mode &= �
#
2;
bu�er :l &= �2;
size = incr (size ;�1);
o = zero octa ;
while (1) f
hRead n < 128 wyde characters into buf 17 i;
mmputchars (buf ; 2 � n+ 2; bu�er );
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;
bu�er = incr (bu�er ; 2 � n);
g
g
ARGS=macro ( ), x2.
feof : int ( ), .
fgets : char �( ), .
fp : FILE �, x5.
h: tetra, x3.
incr : octa ( ), MMIX-ARITH x6.
l: tetra, x3.
mmputchars : extern int ( ),
x4.
mode : int, x5.
neg one : octa, MMIX-ARITH x4.
octa= struct, x3.
s�le : sim �le info [ ], x6.
stdin : FILE �, .
stdin chr : extern char ( ), x4.
zero octa : octa,
MMIX-ARITH x4.
MMIX-IO: INTRODUCTION 144
17. hRead n < 128 wyde characters into buf 17 i �
s = 127;
if (size :l < s ^ :size :h) s = size :l;
if (s�le [handle ]:fp � stdin )
for (p = buf ; n = 0; n < s; ) f
�p
++
= stdin chr ( ); �p
++
= stdin chr ( );
n
++
;
if (�(p� 1) � '\n' ^ �(p� 2) � 0) break;
g
else
for (p = buf ; n = 0; n < s; ) f
if (fread (p; 1; 2; s�le [handle ]:fp ) 6= 2) f
eof = feof (s�le [handle ]:fp);
if (:eof ) return neg one ;
break;
g
n
++
; p += 2;
if (�(p� 1) � '\n' ^ �(p� 2) � 0) break;
g
�p = �(p+ 1) = '\0';
This code is used in section 16.
18. h Subroutines 7 i +�
octa mmix fwrite ARGS((unsigned char;octa;octa));
octa mmix fwrite (handle ; bu�er ; size )
unsigned char handle ;
octa bu�er ; size ;
f
char buf [256];
register int n;
if (:(s�le [handle ]:mode &
#
2)) return ominus (zero octa ; size );
if (s�le [handle ]:mode &
#
8) s�le [handle ]:mode &= �
#
1;
while (1) f
if (size :h _ size :l � 256) n = mmgetchars (buf ; 256; bu�er ;�1);
else n = mmgetchars (buf ; size :l; bu�er ;�1);
size = incr (size ;�n);
if (fwrite (buf ; 1; n; s�le [handle ]:fp) 6= n) return ominus (zero octa ; size );
�ush (s�le [handle ]:fp);
if (:size :l ^ :size :h) return zero octa ;
bu�er = incr (bu�er ; n);
g
g
19. h Subroutines 7 i +�
octa mmix fputs ARGS((unsigned char;octa));
octa mmix fputs (handle ; string )
unsigned char handle ;
octa string ;
f
145 MMIX-IO: INTRODUCTION
char buf [256];
register int n;
octa o;
o = zero octa ;
if (:(s�le [handle ]:mode &
#
2)) return neg one ;
if (s�le [handle ]:mode &
#
8) s�le [handle ]:mode &= �
#
1;
while (1) f
n = mmgetchars (buf ; 256; string ; 0);
if (fwrite (buf ; 1; n; s�le [handle ]:fp) 6= n) return neg one ;
o = incr (o; n);
if (n < 256) f
�ush (s�le [handle ]:fp);
return o;
g
string = incr (string ; n);
g
g
20. h Subroutines 7 i +�
octa mmix fputws ARGS((unsigned char;octa));
octa mmix fputws (handle ; string )
unsigned char handle ;
octa string ;
f
char buf [256];
register int n;
octa o;
o = zero octa ;
if (:(s�le [handle ]:mode &
#
2)) return neg one ;
while (1) f
n = mmgetchars (buf ; 256; string ; 1);
if (fwrite (buf ; 1; n; s�le [handle ]:fp) 6= n) return neg one ;
o = incr (o; n� 1);
if (n < 256) f
�ush (s�le [handle ]:fp);
return o;
g
string = incr (string ; n);
g
g
ARGS=macro ( ), x2.
buf : char [ ], x16.
eof : int, x16.
feof : int ( ), .
�ush : int ( ), .
fp : FILE �, x5.
fread : size t ( ), .
fwrite : size t ( ), .
h: tetra, x3.
handle : unsigned char, x16.
incr : octa ( ), MMIX-ARITH x6.
l: tetra, x3.
mmgetchars : extern int ( ),
x4.
mode : int, x5.
n: register int, x16.
neg one : octa, MMIX-ARITH x4.
octa= struct, x3.
ominus : octa ( ),
MMIX-ARITH x5.
p: register char �, x16.
s: register int, x16.
s�le : sim �le info [ ], x6.
size : octa, x16.
stdin : FILE �, .
stdin chr : extern char ( ), x4.
zero octa : octa,
MMIX-ARITH x4.
MMIX-IO: INTRODUCTION 146
21. #de�ne sign bit ((unsigned)
#
80000000)
hSubroutines 7 i +�
octa mmix fseek ARGS((unsigned char;octa));
octa mmix fseek (handle ; o�set )
unsigned char handle ;
octa o�set ;
f
if (:(s�le [handle ]:mode &
#
4)) return neg one ;
if (s�le [handle ]:mode &
#
8) s�le [handle ]:mode =
#
f;
if (o�set :h& sign bit ) f
if (o�set :h 6=
#
ffffffff _ :(o�set :l & sign bit )) return neg one ;
if (fseek (s�le [handle ]:fp ; (int) o�set :l + 1; SEEK_END) 6= 0) return neg one ;
g else f
if (o�set :h _ (o�set :l & sign bit )) return neg one ;
if (fseek (s�le [handle ]:fp ; (int) o�set :l; SEEK_SET) 6= 0) return neg one ;
g
return zero octa ;
g
22. h Subroutines 7 i +�
octa mmix ftell ARGS((unsigned char));
octa mmix ftell (handle )
unsigned char handle ;
f
register long x;
octa o;
if (:(s�le [handle ]:mode &
#
4)) return neg one ;
x = ftell (s�le [handle ]:fp);
if (x < 0) return neg one ;
o:h = 0; o:l = x;
return o;
g
23. One last subroutine belongs here, just in case the user has modi�ed the standard
error handle.
hSubroutines 7 i +�
void print trip warning ARGS((int;octa));
void print trip warning (n; loc)
int n;
octa loc ;
f
if (s�le [2]:mode &
#
2) fprintf (s�le [2]:fp ; "Warning: %s at location %08x%08x\n";
trip warning [n]; loc :h; loc :l);
g
24. hGlobal variables 6 i +�
char �trip warning [ ] = f"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"g;
147 MMIX-IO: NAMES OF THE SECTIONS
25. Names of the sections.
hExternal subroutines 4 i Used in section 1.
hGlobal variables 6, 9, 24 i Used in section 1.
hPreprocessor macros 2 i Used in section 1.
hRead n < 128 wyde characters into buf 17 i Used in section 16.
hRead n < 256 characters into buf 15 i Used in section 14.
hRead n � size :l characters into buf 13 i Used in section 12.
hSubroutines 7, 8, 10, 11, 12, 14, 16, 18, 19, 20, 21, 22, 23 i Used in section 1.
hType de�nitions 3, 5 i Used in section 1.
ARGS=macro ( ), x2.
fp : FILE �, x5.
fprintf : int ( ), .
fseek : int ( ), .
ftell : long ( ), .
h: tetra, x3.
l: tetra, x3.
mode : int, x5.
neg one : octa, MMIX-ARITH x4.
octa= struct, x3.
SEEK_END=macro, .
SEEK_SET=macro, .
s�le : sim �le info [ ], x6.
zero octa : octa,
MMIX-ARITH x4.
Introduction
Names of the sections
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