Import VBCC source snapshot (29/04/2022)
diff --git a/vsc/vsc.c b/vsc/vsc.c
new file mode 100755
index 0000000..9fc9a25
--- /dev/null
+++ b/vsc/vsc.c
@@ -0,0 +1,239 @@
+/* vsc - portable instruction scheduler for vbcc.   */
+/* (c) 1997-99 by Volker Barthelmann.               */
+
+#include "vsc.h"
+
+char vs_copyright[]="vsc scheduler V0.1 (c) 1997-99 by Volker Barthelmann";
+
+#define MAX_INS 128
+#define LINELENGTH 1024
+
+#ifndef DEBUG
+int DEBUG;
+#endif
+
+struct sinfo silist[MAX_INS];
+int si_count;
+int done;
+
+int bvcmp(unsigned char *dest,unsigned char *src,size_t len)
+/*  vergleicht zwei Bitvektoren    */
+{
+    for(;len>0;len--)
+        if(*dest++!=*src++) return(0);
+    return(1);
+}
+void bvunite(unsigned char *dest,unsigned char *src,size_t len)
+/*  berechnet Vereinigung zweier Bitvektoren    */
+{
+    for(;len>0;len--)
+        *dest++|=*src++;
+}
+void bvintersect(unsigned char *dest,unsigned char *src,size_t len)
+/*  berechnet Durchschnitt zweier Bitvektoren   */
+{
+    for(;len>0;len--)
+        *dest++&=*src++;
+}
+void bvdiff(unsigned char *dest,unsigned char *src,size_t len)
+/*  berechnet 'Differenz' zweier Bitvektoren    */
+{
+    for(;len>0;len--)
+        *dest++&=~(*src++);
+}
+
+void raus(void)
+{
+  sched_cleanup();
+  if(DEBUG&1) printf("raus\n");
+  if(done)
+    exit(EXIT_SUCCESS);
+  else
+    exit(EXIT_FAILURE);
+}
+void *mymalloc(size_t sz)
+{
+  void *p=malloc(sz);
+  if(!p){
+    puts("Out of memory!");
+    raus();
+  }
+  return p;
+}
+void print_sinfo(void)
+{
+  struct sinfo *p;int i,j;
+  if(DEBUG&2)
+    printf("print_sinfo\n");
+  else
+    return;
+  for(j=0;j<si_count;j++){
+    p=&silist[j];
+    printf("inst: %s",p->txt);
+    printf("flags=%u, label=%u latency=%u\n",p->flags,p->label,p->latency);
+    printf("available pipelines: ");
+    for(i=0;i<PIPES;i++)
+      if(BTST(p->pipes,i))
+        printf("%d ",i);
+    printf("\nuses registers (%d=mem): ",MEM);
+    for(i=0;i<=MEM;i++)
+      if(BTST(p->uses,i))
+        printf("%d ",i);
+    printf("\nmodifies registers (%d=MEM): ",MEM);
+    for(i=0;i<=MEM;i++)
+      if(BTST(p->modifies,i))
+        printf("%d ",i);
+    printf("\n\n");
+  }
+}
+void free_sinfo(void)
+{
+  int j;
+  for(j=0;j<si_count;j++)
+    free(silist[j].txt);
+}
+void output_scheduled(FILE *f)
+{
+  int pipes[PIPES],i,j,k,l,remaining;
+  int latency[MEM+1]={0},cycle=0;
+  unsigned char used[REGS_SIZE],modified[REGS_SIZE],tmp[REGS_SIZE],empty[REGS_SIZE]={0};
+  remaining=si_count;
+  if(DEBUG&2) print_sinfo();
+  while(remaining){
+    cycle++;
+    if(DEBUG&4){
+      printf("cycle %d\n",cycle);
+      for(i=0;i<=MEM;i++)
+        if(latency[i]>0) printf("latency[%d]=%d\n",i,latency[i]);
+    }
+    /* Mark all instructions which are ready. */
+    memset(modified,0,REGS_SIZE);
+    memset(used,0,REGS_SIZE);
+    for(i=0;i<si_count;i++){
+      if(silist[i].flags&OUT) continue;
+      memcpy(tmp,silist[i].uses,REGS_SIZE);
+      bvunite(tmp,silist[i].modifies,REGS_SIZE);
+      bvintersect(tmp,modified,REGS_SIZE);
+      if(bvcmp(tmp,empty,REGS_SIZE)){
+        /* uses and modifies nothing that has to be modified before */
+        memcpy(tmp,used,REGS_SIZE);
+        bvintersect(tmp,silist[i].modifies,REGS_SIZE);
+        if(bvcmp(tmp,empty,REGS_SIZE)){
+          /* modifies nothing that has to be used before */
+          for(k=0,j=0;j<=MEM;j++){
+            if(BTST(silist[i].uses,j)&&latency[j]>0) k=1;
+          }
+          if(!k) silist[i].flags|=READY;
+        }
+      }
+      bvunite(modified,silist[i].modifies,REGS_SIZE);
+      bvunite(used,silist[i].uses,REGS_SIZE);
+    }
+
+    /* Fill pipeline slots with ready instructions. */
+    for(i=0;i<PIPES;i++) pipes[i]=-1;
+    for(i=0;i<si_count;i++){
+      if(silist[i].flags&OUT) continue;
+      if(!(silist[i].flags&READY)) continue;
+      if(DEBUG&4) printf("inst ready: %s",silist[i].txt);
+      k=0;
+      /* Is there a free slot? */
+      for(j=0;!k&&j<PIPES;j++){
+        if(pipes[j]<0&&BTST(silist[i].pipes,j)){
+          pipes[j]=i;
+          k=1;
+        }
+      }
+      /* Replace a scheduled instruction with smaller latency. */
+      for(j=0;!k&&j<PIPES;j++){
+        if(BTST(silist[i].pipes,j)&&silist[i].latency>silist[pipes[j]].latency){
+          pipes[j]=i;
+          k=1;
+        }
+      }
+    }
+    if(DEBUG&4) printf("instructions for cycle %d:\n",cycle);
+    for(i=0;i<PIPES;i++){
+      if(pipes[i]>=0){
+        if(DEBUG&4) printf("%3d: %s",i,silist[pipes[i]].txt);
+        fprintf(f,"%s",silist[pipes[i]].txt);
+        silist[pipes[i]].flags|=OUT;
+        remaining--;
+        for(j=0;j<=MEM;j++){
+          if(BTST(silist[pipes[i]].modifies,j)) latency[j]=silist[pipes[i]].latency;
+        }
+      }
+    }
+    for(i=0;i<=MEM;i++)
+      if(latency[i]>0) latency[i]--;
+  }
+}
+int main(int argc,char *argv[])
+{
+  char s[LINELENGTH];int i,quiet=0;
+  FILE *in,*out; char *inname=0,*outname=0;
+  for(i=1;i<argc;i++){
+    if(*argv[i]!='-'){
+      if(!inname){
+        inname=argv[i];
+      }else{
+        if(outname){
+          printf("Only one input file allowed\n");
+          raus();
+        }else{
+          outname=argv[i];
+        }
+      }
+    }else{
+      if(!strcmp("-quiet",argv[i])) {quiet=1;continue;}
+#ifndef DEBUG
+      if(!strncmp("-debug=",argv[i],7)){DEBUG=atoi(argv[i]+7);continue;}
+#endif
+      printf("Unknown option \"%s\"\n",argv[i]);
+      raus();
+    }
+  }
+  if(!sched_init()){printf("sched_init failed\n");raus();}
+  if(!quiet){
+#ifdef SPECIAL_COPYRIGHT
+    printf("%s\n",SPECIAL_COPYRIGHT);
+#else
+    printf("%s\n%s\n",vs_copyright,tg_copyright);
+#endif
+  }
+  if(!inname){printf("No input file\n");raus();}
+  if(!outname){printf("No output file\n");raus();}
+  in=fopen(inname,"r");
+  if(!in){printf("Could not open input file \"%s\"\n",inname);raus();}
+  out=fopen(outname,"w");
+  if(!out){printf("Could not open output file \"%s\"\n",outname);raus();}
+  while(fgets(s,LINELENGTH-1,in)){
+    memset(&silist[si_count],0,sizeof(silist[0]));
+    silist[si_count].txt=mymalloc(strlen(s)+1);
+    strcpy(silist[si_count].txt,s);
+    if(!sched_info(&silist[si_count])){
+      printf("Do not understand instruction:\n%s\n",silist[si_count].txt);
+      raus();
+    }
+    if(silist[si_count].flags&(BARRIER|LABEL|COND_BRANCH|UNCOND_BRANCH)){
+      if(DEBUG&1) printf("Barrier: %s",silist[si_count].txt);
+      output_scheduled(out);
+      free_sinfo();
+      fprintf(out,silist[si_count].txt);
+      si_count=0;
+    }else{
+      if(++si_count>=MAX_INS){
+        if(DEBUG&1) printf("MAX_INS reached: %s",silist[si_count].txt);
+        output_scheduled(out);
+        free_sinfo();
+        si_count=0;
+      }
+    }
+  }
+  output_scheduled(out);
+  free_sinfo();
+  done=1;
+  raus();
+}
+
+