Fix ushot overflow, capitalization

samples/kim1/Makefile

@@ -32,7 +32,8 @@ else
 endif
 
 EXELIST_kim1 = \
-        kimHello.bin
+        kimHello.bin \
+        kimSieve.bin
 
 ifneq ($(EXELIST_$(SYS)),)
 samples: $(EXELIST_$(SYS))
@@ -49,8 +50,13 @@ else
 	@echo > $(NULLDEV)
 endif
 
+kimSieve.bin: kimSieve.c
+	$(CL) -t kim1 -C kim1-60k.cfg -O -o kimSieve.bin kimSieve.c
+
 kimHello.bin: kimHello.c
 	$(CL) -t kim1 -O -o kimHello.bin kimHello.c
 
 clean:
+	@$(DEL) kimSieve.bin 2>$(NULLDEV)
 	@$(DEL) kimHello.bin 2>$(NULLDEV)
+

samples/kim1/kimSieve.c

@@ -0,0 +1,125 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+typedef unsigned char byte;
+typedef unsigned short int ushort;
+typedef unsigned long int  ulong;
+
+#define LIMIT 100000L
+
+// BITARRAY
+// 
+// My bit-access macros pre-divide by two on the presumption that you'll never
+// try try access both odd and even bits!
+
+#define GETBIT(array, bit) (array[bit >> 4]  &  (1 << ((bit >> 1) & 7)))       
+#define SETBIT(array, bit) (array[bit >> 4] |=  (1 << ((bit >> 1) & 7)))
+#define CLRBIT(array, bit) (array[bit >> 4] &= ~(1 << ((bit >> 1) & 7)))
+
+// RepeatChar
+//
+// Outputs a given character N times
+
+void RepeatChar(char c, size_t count)
+{
+   while (count--)
+      putc(c, stdout);
+}
+
+// sqrti
+//
+// Binary search integer square root
+
+ushort sqrti(ulong num)
+{
+    long i;
+    ulong ret = 0;
+
+    for(i = 15; i >= 0; i--)
+    {
+        ulong temp = ret | (1L << (ulong)i);
+        if(temp * temp <= num)
+        {
+            ret = temp;
+        }
+    }
+    return ret;
+}
+
+// main()
+//
+// CC65 main function receives no parameters
+
+int main(void)
+{
+   // CC65 cannot mix code and data so we have to declare all variables here in the function prolog
+
+   ulong iNumber;
+   ushort currentFactor;
+   ulong numBytesAllocated, rootOfLimit;
+   byte *array;
+   ulong countOfPrimes;
+
+   rootOfLimit = sqrti(LIMIT);
+   puts("\r\n\r\n");
+   RepeatChar('*', 70);
+   puts("\r\n** Prime Number Sieve - Dave Plummer 2022                           **");
+   RepeatChar('*', 70);
+   
+   printf("\r\n\r\nCalculating primes to %ld using a sqrt of %ld...\r\n", LIMIT, rootOfLimit);
+
+   // Calculate how much memory should be allocated
+
+   numBytesAllocated = (LIMIT + 15) / 16;
+   array = malloc(numBytesAllocated);
+   if (!array)
+   {
+      printf("Unable to allocate %ld bytes for %ld bits\r\n", numBytesAllocated, LIMIT);
+      return 0;
+   }
+   else
+   {
+      printf("Allocated %ld bytes for %ld slots\r\n", numBytesAllocated, LIMIT);
+      
+      // Preset all the bits to true
+
+      for (iNumber = 0; iNumber < numBytesAllocated; iNumber++)
+         array[iNumber] = 0xFF;
+   }
+
+   // Search for next unmarked factor
+
+   currentFactor = 3;
+   while (currentFactor <= rootOfLimit)
+   {
+      ulong num, n;
+
+      for (num = currentFactor; num <= LIMIT; num += 2)
+      {
+         if (GETBIT(array, num))
+         {
+            currentFactor = num;
+            break;
+         }
+      }
+     
+      for (n = (ulong) currentFactor * currentFactor; n <= LIMIT; n += currentFactor * 2)
+         CLRBIT(array, n);
+
+      currentFactor += 2;
+   }
+
+   // Display results
+   //
+   // printf("The following primes were found at or below %ld:\r\n2, ", LIMIT);
+
+   countOfPrimes = 1;
+   for (iNumber = 3; iNumber <= LIMIT; iNumber += 2)
+      if (GETBIT(array, iNumber))
+         countOfPrimes++;
+
+   printf("[END: Count = %ld]\r\n", countOfPrimes);
+
+   free(array);
+   return 1;
+}