Added some reading material, floating point support.

git-svn-id: http://www.cdkersey.com/harp/harptool@9 0246edb2-e076-4747-b392-db732a341fa2

src/include/harpfloat.h

@@ -0,0 +1,123 @@
+/*******************************************************************************
+ HARPtools by Chad D. Kersey, Summer 2011
+*******************************************************************************/
+#include <math.h>
+#include <stdlib.h>
+
+#include "types.h"
+
+#ifdef DEBUG
+#include <iostream>
+
+#define DEBUGMSG(x) do { \
+  std::cout << __FILE__ << ':' <<__LINE__ << ": " << x << '\n'; \
+} while(0)
+#else
+#define DEBUGMSG(x) do { } while(0)
+#endif
+
+namespace Harp {
+  // This class serves to handle the strange-precision floating point that can 
+  // crop up in HARP. 
+  class Float {
+  public:
+    Float(Word_u bin, Size n): sz(n) {
+      DEBUGMSG("Float(0x" << std::hex << bin << ", " << std::dec << n << ')');
+      
+      bool sign(bin >> (n*8 - 1));
+      
+      Size expSz;
+      if (n < 4) {
+        expSz = 5;
+      } else if (n < 8) {
+        expSz = 8;
+      } else {
+        expSz = 11;
+      }
+
+      Size sigSz = n*8 - expSz - 1;
+
+      DEBUGMSG("  exp: " << std::dec << expSz <<
+               " bits, sig: " << std::dec << sigSz << " bits.");
+
+      int exp = (bin >> sigSz) & ((1<<expSz) - 1);
+      Word_u sig = bin & ((1llu<<sigSz) - 1);
+      DEBUGMSG("  sig=" << std::dec << sig << " exp=" << exp);
+
+      if (exp == 0) {
+        // Subnormal 
+        d = sig / pow(2, ((1<<(expSz-1))-2)) / pow(2, sigSz);
+        DEBUGMSG("  Denorm.");
+      } else if (exp == ((1<<expSz) - 1)) {
+        // Infinity
+        d = HUGE_VAL;
+        DEBUGMSG("  Inf.");
+      } else {
+        // Normalized, implied 1.
+        exp -= (1<<(expSz - 1)) - 1;
+        d = pow(2.0, exp - int(sigSz)) * double((1ll << sigSz) + sig);
+        DEBUGMSG("  Norm, exp=" << exp);
+      }
+
+      if (sign) d = -d;
+
+      DEBUGMSG("Set to " << d);
+    }
+
+    Float(double d, Size n): sz(n), d(d) { DEBUGMSG("Float(double, size)"); }
+
+    operator Word_u() {
+      DEBUGMSG("Float -> Word_u: " << d);
+      Size expSz;
+      if (sz < 4) {
+        expSz = 5;
+      } else if (sz < 8) {
+        expSz = 8;
+      } else {
+        expSz = 11;
+      }
+
+      Size sigSz = 8*sz - expSz - 1;
+
+      bool sign(d < 0);
+
+      bool inf(isinf(d)), zero(d == 0.0);
+      int exp;
+
+      if (!inf && !zero) exp = floor(log2(fabs(d)));
+
+      Word_u rval;
+      if (inf) {
+        // Infinity
+        DEBUGMSG("  Inf.");
+        rval = ((1llu<<expSz)-1llu)<<sigSz;
+      } else if (!zero && abs(exp) < (1<<(expSz-1)) - 1) {
+        // Normalized with implied 1.
+        Word_u sig = (fabs(d) * pow(2.0, -exp) - 1.0) * pow(2.0, sigSz);
+        DEBUGMSG("  Norm, exp=" << exp << ", sig=" << sig);
+        rval = ((((exp + ((1llu<<(expSz-1)) - 1llu))
+                                          &((1llu<<expSz)-1llu)))<<sigSz) | sig;
+      } else if (!zero && exp > -(1<<(expSz-1)) - sigSz) {
+        // Subnormal number.
+        Word_u sig = round(fabs(d)*pow(2.0,((1<<(expSz-1))-2))*pow(2.0, sigSz));
+        DEBUGMSG("  Denorm, exp=" << exp << ", sig=" << sig);
+        rval = sig;
+      } else {
+        // Zero.
+        rval = 0;
+      }
+      
+      if (sign) rval |= 1llu<<(sz*8 - 1);
+
+      DEBUGMSG("  Returning 0x" << std::hex << rval);
+
+      return rval;
+    }
+
+    operator double() { DEBUGMSG("Float->double " << d); return d; }
+
+  private:
+    double d;
+    Size sz;
+  };
+};

src/include/instruction.h

@@ -29,7 +29,8 @@ namespace Harp {
                   ANDI, ORI, XORI, ADDI, SUBI, MULI, DIVI, MODI, SHLI, SHRI,
                   JALI, JALR, JMPI, JMPR, CLONE, JALIS, JALRS, 
                   JMPRT, LD, ST, LDI, RTOP, ANDP, ORP, XORP, NOTP, ISNEG, 
-                  ISZERO, HALT, TRAP, JMPRU, SKEP, RETI, TLBRM };
+                  ISZERO, HALT, TRAP, JMPRU, SKEP, RETI, TLBRM,
+                  ITOF, FTOI, FADD, FSUB, FMUL, FDIV, FNEG };
     enum ArgClass {
       AC_NONE, AC_2REG, AC_2IMM, AC_3REG, AC_3PREG, AC_3IMM, AC_3REGSRC, 
       AC_1IMM, AC_1REG, AC_3IMMSRC, AC_PREG_REG, AC_2PREG

src/include/types.h

@@ -12,8 +12,8 @@ namespace Harp {
   typedef uint64_t Word_u;
   typedef int64_t  Word_s;
 
-  typedef Word     Addr;
-  typedef Word     Size;
+  typedef Word_u   Addr;
+  typedef Word_u   Size;
 
   typedef unsigned RegNum;
   typedef unsigned ThdNum;