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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{MMMIX}

\def\MMIX{\.{MMIX}}

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

@s octa int

@s tetra int

@s bool int

@s fetch int

@s specnode int

@* Introduction.

This \.{CWEB} program simulates how the \MMIX\ computer might be

implemented with a high-performance pipeline in many different configurations.

All of the complexities of \MMIX's architecture are treated, except for

multiprocessing and low-level details of memory mapped input/output.

The present program module, which contains the main routine for the

\MMIX\ meta-simulator, is primarily devoted to administrative tasks. Other modules

do the actual work after this module has told them what to do.

@ A user typically invokes the meta-simulator with a \UNIX/-like command line

of the general form

`\.{mmmix}~\.{configfile}~\.{progfile}',

where the \.{configfile} describes the characteristics

of an \MMIX\ implementation and the \.{progfile} contains a program to

be downloaded and run. Rules for configuration files appear in

the module called \.{mmix-config}. The program file is either

an ``\MMIX\ binary file'' dumped by {\mc MMIX-SIM}, or an

ASCII text file that describes hexadecimal data

in a rudimentary format. It is assumed to be binary if

its name ends with the extension `\.{.mmb}'.

@c

#include 

#include 

#include 

#include "mmix-pipe.h"

@#

char *config_file_name, *prog_file_name;

@@;

@@;

int main(argc,argv)

  int argc;

  char *argv[];

{

  @;

  MMIX_config(config_file_name);

  MMIX_init();

  mmix_io_init();

  @;

  @;

  printf("Simulation ended at time %d.\n",ticks.l);

  print_stats();

  return 0;

}

@ The command line might also contain options, some day.

For now I'm forgetting them and simplifying everything until I gain

further experience.

@=

if (argc!=3) {

  fprintf(stderr,"Usage: %s configfile progfile\n",argv[0]);

@.Usage: ...@>

  exit(-3);

}

config_file_name=argv[1];

prog_file_name=argv[2];

@ @=

if (strlen(prog_file_name)>4 &&

     strcmp(prog_file_name+strlen(prog_file_name)-4,".mmb")==0)

  @@;

else @;

fclose(prog_file);

@* Hexadecimal input to memory.

A rudimentary hexadecimal input format is implemented here so that the

@^hexadecimal files@>

simulator can be run with essentially arbitrary data in the simulated memory.

The rules of this format are extremely simple: Each line of the file

either begins with (i)~12 hexadecimal digits followed by a colon; or

(ii)~a space followed by 16 hexadecimal digits. In case~(i), the 12

hex digits specify a 48-bit physical address, called the current

location. In case~(ii), the 16 hex digits specify an octabyte to be

stored in the current location; the current location is then increased by~8.

The current location should be a multiple of~8, but its three least

significant bits are actually ignored. Arbitrary comments can follow

the specification of a new current location or a new octabyte, as long

as each line is less than 99 characters long. For example, the file

$$\vbox{\halign{\tt#\hfil\cr

0123456789ab: SILLY EXAMPLE\cr

\ 0123456789abcdef first octabyte\cr

\ fedbca9876543210 second\cr}}$$

places the octabyte

\Hex{0123456789abcdef} into memory location \Hex{0123456789a8}

and \Hex{fedcba9876543210} into location \Hex{0123456789b0}.

@d BUF_SIZE 100

@=

octa cur_loc;

octa cur_dat;

bool new_chunk;

char buffer[BUF_SIZE];

FILE *prog_file;

@ @=

{

  prog_file=fopen(prog_file_name,"r");

  if (!prog_file) {

    fprintf(stderr,"Panic: Can't open MMIX hexadecimal file %s!\n",prog_file_name);

@.Can't open...@>

    exit(-3);

  }

  new_chunk=true;

  while (1) {

    if (!fgets(buffer,BUF_SIZE,prog_file)) break;

    if (buffer[strlen(buffer)-1]!='\n') {

      fprintf(stderr,"Panic: Hexadecimal file line too long: `%s...'!\n",buffer);

@.Hexadecimal file line...@>

      exit(-3);

    }

    if (buffer[12]==':') @@;

    else if (buffer[0]==' ') @@;

    else {

      fprintf(stderr,"Panic: Improper hexadecimal file line: `%s'!\n",buffer);

@.Improper hexadecimal...@>

      exit(-3);

    }

  }

}

@ @=

{

  if (sscanf(buffer,"%4x%8x",&cur_loc.h,&cur_loc.l)!=2) {

    fprintf(stderr,"Panic: Improper hexadecimal file location: `%s'!\n",buffer);

@.Improper hexadecimal...@>

    exit(-3);

  }

  new_chunk=true;

}

@ @=

{

  if (sscanf(buffer+1,"%8x%8x",&cur_dat.h,&cur_dat.l)!=2) {

    fprintf(stderr,"Panic: Improper hexadecimal file data: `%s'!\n",buffer);

@.Improper hexadecimal...@>

    exit(-3);

  }

  if (new_chunk) mem_write(cur_loc,cur_dat);

  else mem_hash[last_h].chunk[(cur_loc.l&0xffff)>>3]=cur_dat;

  cur_loc.l+=8;

  if ((cur_loc.l&0xfff8)!=0) new_chunk=false;

  else {

    new_chunk=true;

    if ((cur_loc.l&0xffff0000)==0) cur_loc.h++;

  }

}

@* Binary input to memory.

When the program file was dumped by {\mc MMIX-SIM}, it

has the simple format discussed in exercise 1.4.3$'$--20 of the \MMIX\ fascicle.

@^binary files@>

@^segments@>

In this case we assume that the user's program has text, data, pool, and stack

segments, as in the conventions of that book.

We load it into four

$2^{32}$-byte pages of physical memory, one for each segment; page zero of

segment~$i$ is mapped to physical location $2^{32}i$. Page tables are kept in

physical locations starting at $2^{32}\times4$; static traps begin at

$2^{32}\times 5$ and dynamic traps at $2^{32}\times6$. (These conventions

agree with the special register settings

$\rm rT=\Hex{8000000500000000}$,

$\rm rTT=\Hex{8000000600000000}$,

$\rm rV=\Hex{369c200400000000}$

assumed by the stripped-down simulator.)

@=

{

  prog_file=fopen(prog_file_name,"rb");

  if (!prog_file) {

    fprintf(stderr,"Panic: Can't open MMIX binary file %s!\n",prog_file_name);

@.Can't open...@>

    exit(-3);

  }

  while (1) {

    if (!undump_octa()) break;

    new_chunk=true;

    cur_loc=cur_dat;

    if (cur_loc.h&0x9fffffff) bad_address=true;

    else bad_address=false, cur_loc.h >>= 29;

         /* apply trivial mapping function for each segment */

    @;

  }

  @;

}

@ The |undump_octa| routine reads eight bytes from the binary file

|prog_file| into the global octabyte |cur_dat|,

taking care as usual to be big-endian regardless of the host computer's bias.

@^big-endian versus little-endian@>

@^little-endian versus big-endian@>

@=

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

static bool undump_octa()

{

  register int t0,t1,t2,t3;

  t0=fgetc(prog_file);@+ if (t0==EOF) return false;

  t1=fgetc(prog_file);@+ if (t1==EOF) goto oops;

  t2=fgetc(prog_file);@+ if (t2==EOF) goto oops;

  t3=fgetc(prog_file);@+ if (t3==EOF) goto oops;

  cur_dat.h=(t0<<24)+(t1<<16)+(t2<<8)+t3;

  t0=fgetc(prog_file);@+ if (t0==EOF) goto oops;

  t1=fgetc(prog_file);@+ if (t1==EOF) goto oops;

  t2=fgetc(prog_file);@+ if (t2==EOF) goto oops;

  t3=fgetc(prog_file);@+ if (t3==EOF) goto oops;

  cur_dat.l=(t0<<24)+(t1<<16)+(t2<<8)+t3;

  return true;

oops: fprintf(stderr,"Premature end of file on %s!\n",prog_file_name);

@.Premature end of file...@>

  return false;

}

@ @=

while (1) {

  if (!undump_octa()) {

    fprintf(stderr,"Unexpected end of file on %s!\n",prog_file_name);

@.Unexpected end of file...@>

    break;

  }

  if (!(cur_dat.h || cur_dat.l)) break;

  if (bad_address) {

    fprintf(stderr,"Panic: Unsupported virtual address %08x%08x!\n",

@.Unsupported virtual address@>

                     cur_loc.h,cur_loc.l);

    exit(-5);

  }

  if (new_chunk) mem_write(cur_loc,cur_dat);

  else mem_hash[last_h].chunk[(cur_loc.l&0xffff)>>3]=cur_dat;

  cur_loc.l+=8;

  if ((cur_loc.l&0xfff8)!=0) new_chunk=false;

  else {

    new_chunk=true;

    if ((cur_loc.l&0xffff0000)==0) {

      bad_address=true; cur_loc.h=(cur_loc.h<<29)+1;

    }

  }

}

@ The primitive operating system assumed in simple programs of {\sl The

Art of Computer Programming\/} will set up text segment, data segment,

pool segment, and stack segment as in {\mc MMIX-SIM}. The runtime stack

will be initialized if we \.{UNSAVE} from the last location loaded

in the \.{.mmb} file.

@d rQ 16

@=

if (cur_loc.h!=3) {

  fprintf(stderr,"Panic: MMIX binary file didn't set up the stack!\n");

@.MMIX binary file...@>

  exit(-6);

}

inst_ptr.o=mem_read(incr(cur_loc,-8*14)); /* \.{Main} */

inst_ptr.p=NULL;

cur_loc.h=0x60000000;

g[255].o=incr(cur_loc,-8); /* place to \.{UNSAVE} */

cur_dat.l=0x90;

if (mem_read(cur_dat).h) inst_ptr.o=cur_dat; /* start at |0x90| if nonzero */

head->inst=(UNSAVE<<24)+255, tail--; /* prefetch a fabricated command */

head->loc=incr(inst_ptr.o,-4); /* in case the \.{UNSAVE} is interrupted */

g[rT].o.h=0x80000005, g[rTT].o.h=0x80000006;

cur_dat.h=(RESUME<<24)+1, cur_dat.l=0, cur_loc.h=5, cur_loc.l=0;

mem_write(cur_loc,cur_dat); /* the primitive trap handler */

cur_dat.l=cur_dat.h, cur_dat.h=(NEGI<<24)+(255<<16)+1;

cur_loc.h=6, cur_loc.l=8;

mem_write(cur_loc,cur_dat); /* the primitive dynamic trap handler */

cur_dat.h=(GET<<24)+rQ, cur_dat.l=(PUTI<<24)+(rQ<<16), cur_loc.l=0;

mem_write(cur_loc,cur_dat); /* more of the primitive dynamic trap handler */

cur_dat.h=0, cur_dat.l=7; /* generate a PTE with \.{rwx} permission */

cur_loc.h=4; /* beginning of skeleton page table */

mem_write(cur_loc,cur_dat); /* PTE for the text segment */

ITcache->set[0][0].tag=zero_octa;

ITcache->set[0][0].data[0]=cur_dat; /* prime the IT cache */

cur_dat.l=6; /* PTE with read and write permission only */

cur_dat.h=1, cur_loc.l=3<<13;

mem_write(cur_loc,cur_dat); /* PTE for the data segment */

cur_dat.h=2, cur_loc.l=6<<13;

mem_write(cur_loc,cur_dat); /* PTE for the pool segment */

cur_dat.h=3, cur_loc.l=9<<13;

mem_write(cur_loc,cur_dat); /* PTE for the stack segment */

g[rK].o=neg_one; /* enable all interrupts */

g[rV].o.h=0x369c2004;

page_bad=false, page_r=4<<(32-13), page_s=32, page_mask.l=0xffffffff;

page_b[1]=3, page_b[2]=6, page_b[3]=9, page_b[4]=12;

@* Interaction. When prompted for instructions, this simulator

@.mmmix>@>

understands the following terse commands:

\def\bull{\smallbreak\textindent{$\bullet$}}

\def\<#1>{$\langle\,$#1$\,\rangle$}

\bull\: Run for this many clock cycles.

\bull\.{@@}\: Set the instruction pointer

to this virtual address; successive instructions will be fetched from here.

\bull\.{b}\: Set the breakpoint

to this virtual address; simulation will pause when an instruction from the

breakpoint address enters the fetch buffer.

\bull\.v\: Set the desired level of diagnostic

output; each bit in the hexadecimal integer enables certain printouts

when the simulator is running. Bit \Hex1 shows instructions when issued,

deissued, or committed; \Hex2 shows the pipeline and locks after each cycle;

\Hex4 shows each coroutine activation; \Hex8 each coroutine scheduling;

\Hex{10} reports when reading from an uninitialized chunk of memory;

\Hex{20} asks for online input when reading from addresses $\ge2^{48}$;

\Hex{40} reports all I/O to memory address $\ge2^{48}$;

\Hex{80} shows details of branch prediction;

\Hex{100} displays full cache contents including blocks with invalid tags.

\bull\.-\: Deissue this many instructions.

\bull\.l\ or \.g\: Show current ``hot'' contents

of a local or global register.

\bull\.m\: Show current contents of a physical memory

address. (This value may not be up to date; newer values might appear

in the write buffer and/or in the caches.)

\bull\.f\: Insert a tetrabyte into the fetch buffer.

(Use with care!)

\bull\.i\: Set the interval counter rI to the given value; this will

trigger an interrupt after the specified number of cycles.

\bull\.{IT}, \.{DT}, \.I, \.D, or \.S: Show current contents of a cache.

\bull\.{D*} or \.{S*}: Show dirty blocks of a cache.

\bull\.p: Show current contents of the pipeline.

\bull\.s: Show current statistics on branch prediction and

speed of instruction issue.

\bull\.h: Help (show the possibilities for interaction).

\bull\.q: Quit.

@=

while (1) {

  printf("mmmix> ");@+fflush(stdout);

@.mmmix>@>

  fgets(buffer,BUF_SIZE,stdin);

  switch (buffer[0]) {

default: what_say:

  printf("Eh? Sorry, I don't understand. (Type h for help)\n");

  continue;

case 'q': case 'x': goto done;

  @@;

  }

}

done:@;

@ @=

case 'h': case '?': printf("The interactive commands are as follows:\n");

  printf("  to run for n cycles\n");

  printf(" @@ to take next instruction from location x\n");

  printf(" b to pause when location x is fetched\n");

  printf(" v to print specified diagnostics when running;\n");

  printf("    x=1[insts enter/leave pipe]+2[whole pipeline each cycle]+\n");

  printf("      4[coroutine activations]+8[coroutine scheduling]+\n");

  printf("      10[uninitialized read]+20[online I/O read]+\n");

  printf("      40[I/O read/write]+80[branch prediction details]+\n");

  printf("      100[invalid cache blocks displayed too]\n");

  printf(" - to deissue n instructions\n");

  printf(" l to print current value of local register n\n");

  printf(" g to print current value of global register n\n");

  printf(" m to print current value of memory address x\n");

  printf(" f to insert instruction x into the fetch buffer\n");

  printf(" i to initiate a timer interrupt after n cycles\n");

  printf(" IT, DT, I, D, or S to print current cache contents\n");

  printf(" D* or S* to print dirty blocks of a cache\n");

  printf(" p to print current pipeline contents\n");

  printf(" s to print current stats\n");

  printf(" h to print this message\n");

  printf(" q to exit\n");

  printf("(Here  is a decimal integer,  is hexadecimal.)\n");

  continue;

@ @=

case '0': case '1': case '2': case '3': case '4':

case '5': case '6': case '7': case '8': case '9':

  if (sscanf(buffer,"%d",&n)!=1) goto what_say;

  printf("Running %d at time %d",n,ticks.l);

  if (bp.h==(tetra)-1 && bp.l==(tetra)-1) printf("\n");

  else printf(" with breakpoint %08x%08x\n",bp.h,bp.l);

  MMIX_run(n,bp);@+continue;

case '@@': inst_ptr.o=read_hex(buffer+1);@+inst_ptr.p=NULL;@+continue;

case 'b': bp=read_hex(buffer+1);@+continue;

case 'v': verbose=read_hex(buffer+1).l;@+continue;

@ @=

int n,m; /* temporary integer */

octa bp={-1,-1}; /* breakpoint */

octa tmp; /* an octabyte of temporary interest */

static unsigned char d[BUF_SIZE];

@ Here's a simple program to read an octabyte in hexadecimal notation

from a buffer. It changes the buffer by storing a null character

after the input.

@^radix conversion@>

@=

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

octa read_hex(p)

  char *p;

{

  register int j,k;

  octa val;

  val.h=val.l=0;

  for (j=0;;j++) {

    if (p[j]>='0' && p[j]<='9') d[j]=p[j]-'0';

    else if (p[j]>='a' && p[j]<='f') d[j]=p[j]-'a'+10;

    else if (p[j]>='A' && p[j]<='F') d[j]=p[j]-'A'+10;

    else break;

  }

  p[j]='\0';

  for (j--,k=0;k<=j;k++) {

    if (k>=8) val.h+=d[j-k]<<(4*k-32);

    else val.l+=d[j-k]<<(4*k);

  }

  return val;

}

@ @=

case '-':@+ if (sscanf(buffer+1,"%d",&n)!=1 || n<0) goto what_say;

  if (cool<=hot) m=hot-cool;@+else m=(hot-reorder_bot)+1+(reorder_top-cool);

  if (n>m) deissues=m;@+else deissues=n;

  continue;

case 'l':@+ if (sscanf(buffer+1,"%d",&n)!=1 || n<0) goto what_say;

  if (n>=lring_size) goto what_say;

  printf("  l[%d]=%08x%08x\n",n,l[n].o.h,l[n].o.l);@+continue;

case 'm': tmp=mem_read(read_hex(buffer+1));

  printf("  m[%s]=%08x%08x\n",buffer+1,tmp.h,tmp.l);@+continue;

@ The register stack pointers, rO and rS, are not kept up to date

in the |g| array. Therefore we have to deduce their values by

examining the pipeline.

@=

case 'g':@+ if (sscanf(buffer+1,"%d",&n)!=1 || n<0) goto what_say;

  if (n>=256) goto what_say;

  if (n==rO || n==rS) {

    if (hot==cool) /* pipeline empty */

      g[rO].o=sl3(cool_O), g[rS].o=sl3(cool_S);

    else g[rO].o=sl3(hot->cur_O), g[rS].o=sl3(hot->cur_S);

  }

  printf("  g[%d]=%08x%08x\n",n,g[n].o.h,g[n].o.l);

  continue;

@ @=

static octa sl3 @,@,@[ARGS((octa))@];@+@t}\6{@>

static octa sl3(y) /* shift left by 3 bits */

  octa y;

{

  register tetra yhl=y.h<<3, ylh=y.l>>29;

    y.h=yhl+ylh;@+ y.l<<=3;

  return y;

}

@ @=

case 'I': print_cache(buffer[1]=='T'? ITcache: Icache,false);@+continue;

case 'D': print_cache(buffer[1]=='T'? DTcache: Dcache,@/

       buffer[1]=='*');@+continue;

case 'S': print_cache(Scache,buffer[1]=='*');@+continue;

case 'p': print_pipe();@+print_locks();@+continue;

case 's': print_stats();@+continue;

case 'i':@+ if (sscanf(buffer+1,"%d",&n)==1) g[rI].o=incr(zero_octa,n);

  continue;

@ @=

case 'f': tmp=read_hex(buffer+1);

 {

   register fetch* new_tail;

   if (tail==fetch_bot) new_tail=fetch_top;

   else new_tail=tail-1;

   if (new_tail==head) printf("Sorry, the fetch buffer is full!\n");

   else {

     tail->loc=inst_ptr.o;

     tail->inst=tmp.l;

     tail->interrupt=0;

     tail->noted=false;

     tail=new_tail;

   }

   continue;

 }

@ A hidden case here, for me when debugging.

It essentially disables the translation caches, by mapping everything

to zero.

@=

case 'd':@+if (ticks.l)

   printf("Sorry: I disable ITcache and DTcache only at the beginning!\n");

 else {

   ITcache->set[0][0].tag=zero_octa;

   ITcache->set[0][0].data[0]=seven_octa;

   DTcache->set[0][0].tag=zero_octa;

   DTcache->set[0][0].data[0]=seven_octa;

   g[rK].o=neg_one;

   page_bad=false;

   page_mask=neg_one;

   inst_ptr.p=(specnode*)1;

 }@+continue;

@ And another case, for me when kludging. At the moment,

it simply lists the functional unit names.

But I might decide to put other stuff here when giving a demo.

@=

case 'k':@+ { register int j;

   for (j=0;j

     printf("unit %s %d\n",funit[j].name,funit[j].k);

 }

 continue;

@ @=

bool bad_address;

extern bool page_bad;

extern octa page_mask;

extern int page_r,page_s,page_b[5];

extern octa zero_octa;

extern octa neg_one;

octa seven_octa={0,7};

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

  /* unsigned $y+\delta$ ($\delta$ is signed) */

extern void mmix_io_init @,@,@[ARGS((void))@];

extern void MMIX_config @,@,@[ARGS((char*))@];

@* Index.