Fix sqrt confusion. There must be a separate isqrt

for the integer square root.

* arith.c (sqroot_fixnum): Renamed back to isqrt_fixnum.
(sqroot): Rewritten to handle only floating-point square root.
(isqrt): New function, based on previous sqroot,
handles only integers.

* eval.c (eval_init): New intrinsic, isqrt.

* lib.h (isqrt): New declaration.

* txr.1: Doc stubs.

* txr.vim: Highlighting for isqrt.

1 files changed, 10 insertions, 12 deletions

diff --git a/arith.c b/arith.c
index a820dc8e..27ac3faf 100644
--- a/arith.c
+++ b/arith.c
@@ -1225,7 +1225,7 @@ inval:
             base, exp, mod, nao);
 }
 
-static int_ptr_t sqroot_fixnum(int_ptr_t a)
+static int_ptr_t isqrt_fixnum(int_ptr_t a)
 {
   int_ptr_t mask = (int_ptr_t) 1 << (highest_bit(a) / 2);
   int_ptr_t root = 0;
@@ -1239,7 +1239,7 @@ static int_ptr_t sqroot_fixnum(int_ptr_t a)
   return root;
 }
 
-val sqroot(val anum)
+val isqrt(val anum)
 {
   switch (type(anum)) {
   case NUM:
@@ -1247,7 +1247,7 @@ val sqroot(val anum)
       cnum a = c_num(anum);
       if (a < 0)
         goto negop;
-      return num_fast(sqroot_fixnum(c_num(anum)));
+      return num_fast(isqrt_fixnum(c_num(anum)));
     }
   case BGNUM:
     {
@@ -1256,20 +1256,13 @@ val sqroot(val anum)
         goto negop;
       return normalize(n);
     }
-  case FLNUM:
-    {
-      double a = c_flo(anum);
-      if (a < 0)
-        goto negop;
-      return flo(sqrt(a));
-    }
   default:
     break;
   }
 
-  uw_throwf(error_s, lit("sqrt: invalid operand ~s"), anum, nao);
+  uw_throwf(error_s, lit("isqrt: non-integer operand ~s"), anum, nao);
 negop:
-  uw_throw(error_s, lit("sqrt: negative operand"));
+  uw_throw(error_s, lit("isqrt: negative operand"));
 }
 
 val gcd(val anum, val bnum)
@@ -1326,6 +1319,11 @@ val loga(val num)
   return flo(log(c_flo(to_float(lit("log"), num))));
 }
 
+val sqroot(val num)
+{
+  return flo(sqrt(c_flo(to_float(lit("sqrt"), num))));
+}
+
 /*
  * TODO: replace this text-based hack!
  */