diff --git a/src/c/numbers/abs.d b/src/c/numbers/abs.d
index 4f938c462..454142000 100644
--- a/src/c/numbers/abs.d
+++ b/src/c/numbers/abs.d
@@ -15,6 +15,7 @@
     See file '../Copyright' for full details.
 */
 
+#include <stdlib.h>
 #define ECL_INCLUDE_MATH_H
 #include <ecl/ecl.h>
 #include <ecl/internal.h>
@@ -26,10 +27,23 @@ cl_abs(cl_object x)
         @(return ecl_abs(x));
 }
 
+static cl_object
+ecl_abs_fixnum(cl_object x)
+{
+        return ecl_fixnum_minusp(x)? ecl_make_integer(-fix(x)) : x;
+}
+
+static cl_object
+ecl_abs_bignum(cl_object x)
+{
+        return (_ecl_big_sign(x) < 0)? _ecl_big_negate(x) : x;
+}
+
 static cl_object
 ecl_abs_rational(cl_object x)
 {
-        return (ecl_minusp(x))? ecl_negate(x) : x;
+        return (ecl_minusp(x->ratio.num))?
+                ecl_make_ratio(ecl_negate(x->ratio.num), x->ratio.den) : x;
 }
 
 static cl_object
@@ -80,6 +94,6 @@ ecl_abs_complex(cl_object x)
 }
 
 MATH_DEF_DISPATCH1(abs, @[abs], @[number],
-                   ecl_abs_rational, ecl_abs_single_float,
-                   ecl_abs_double_float, ecl_abs_long_float,
+                   ecl_abs_fixnum, ecl_abs_bignum, ecl_abs_rational,
+                   ecl_abs_single_float, ecl_abs_double_float, ecl_abs_long_float,
                    ecl_abs_complex);
diff --git a/src/c/numbers/cos.d b/src/c/numbers/cos.d
index 36449565f..c1cf49f93 100644
--- a/src/c/numbers/cos.d
+++ b/src/c/numbers/cos.d
@@ -68,6 +68,6 @@ ecl_cos_complex(cl_object x)
 }
 
 MATH_DEF_DISPATCH1(cos, @[cos], @[number],
-                   ecl_cos_rational, ecl_cos_single_float,
-                   ecl_cos_double_float, ecl_cos_long_float,
+                   ecl_cos_rational, ecl_cos_rational, ecl_cos_rational,
+                   ecl_cos_single_float, ecl_cos_double_float, ecl_cos_long_float,
                    ecl_cos_complex);
diff --git a/src/c/numbers/cosh.d b/src/c/numbers/cosh.d
index b5c631a1d..a5f759ad5 100644
--- a/src/c/numbers/cosh.d
+++ b/src/c/numbers/cosh.d
@@ -71,6 +71,6 @@ ecl_cosh_complex(cl_object x)
 }
 
 MATH_DEF_DISPATCH1(cosh, @[cosh], @[number],
-                   ecl_cosh_rational, ecl_cosh_single_float,
-                   ecl_cosh_double_float, ecl_cosh_long_float,
+                   ecl_cosh_rational, ecl_cosh_rational, ecl_cosh_rational,
+                   ecl_cosh_single_float, ecl_cosh_double_float, ecl_cosh_long_float,
                    ecl_cosh_complex);
diff --git a/src/c/numbers/exp.d b/src/c/numbers/exp.d
index 50f431c2b..afb4905d2 100644
--- a/src/c/numbers/exp.d
+++ b/src/c/numbers/exp.d
@@ -67,6 +67,6 @@ ecl_exp_complex(cl_object x)
 }
 
 MATH_DEF_DISPATCH1(exp, @[exp], @[number],
-                   ecl_exp_rational, ecl_exp_single_float,
-                   ecl_exp_double_float, ecl_exp_long_float,
+                   ecl_exp_rational, ecl_exp_rational, ecl_exp_rational,
+                   ecl_exp_single_float, ecl_exp_double_float, ecl_exp_long_float,
                    ecl_exp_complex);
diff --git a/src/c/numbers/log.d b/src/c/numbers/log.d
index 346e1a10b..a70728280 100644
--- a/src/c/numbers/log.d
+++ b/src/c/numbers/log.d
@@ -50,23 +50,25 @@ ecl_log1_complex_inner(cl_object r, cl_object i)
 	return ecl_make_complex(a, p);
 }
 
+static cl_object
+ecl_log1_bignum(cl_object x)
+{
+        if (ecl_minusp(x)) {
+                return ecl_log1_complex_inner(x, MAKE_FIXNUM(0));
+        } else {
+                cl_fixnum l = ecl_integer_length(x) - 1;
+                cl_object r = ecl_make_ratio(x, ecl_ash(MAKE_FIXNUM(1), l));
+                float d = logf(number_to_float(r)) + l * logf(2.0);
+                return ecl_make_singlefloat(d);
+        }
+}
+
 static cl_object
 ecl_log1_rational(cl_object x)
 {
-        if (type_of(x) == t_bignum) {
-                if (ecl_minusp(x)) {
-                        return ecl_log1_complex_inner(x, MAKE_FIXNUM(0));
-                } else {
-                        cl_fixnum l = ecl_integer_length(x) - 1;
-                        cl_object r = ecl_make_ratio(x, ecl_ash(MAKE_FIXNUM(1), l));
-                        float d = logf(number_to_float(r)) + l * logf(2.0);
-                        return ecl_make_singlefloat(d);
-                }
-        } else {
-  		float f = number_to_float(x);
-		if (f < 0) return ecl_log1_complex_inner(x, MAKE_FIXNUM(0));
-		return ecl_make_singlefloat(logf(number_to_float(x)));
-        }
+        float f = number_to_float(x);
+        if (f < 0) return ecl_log1_complex_inner(x, MAKE_FIXNUM(0));
+        return ecl_make_singlefloat(logf(number_to_float(x)));
 }
 
 static cl_object
@@ -105,8 +107,8 @@ ecl_log1_complex(cl_object x)
 }
 
 MATH_DEF_DISPATCH1(log1, @[log], @[number],
-                   ecl_log1_rational, ecl_log1_single_float,
-                   ecl_log1_double_float, ecl_log1_long_float,
+                   ecl_log1_rational, ecl_log1_bignum, ecl_log1_rational,
+                   ecl_log1_single_float, ecl_log1_double_float, ecl_log1_long_float,
                    ecl_log1_complex);
 
 cl_object
@@ -177,13 +179,9 @@ ecl_log1p_simple(cl_object x)
 static cl_object
 ecl_log1p_rational(cl_object x)
 {
-        if (type_of(x) == t_bignum) {
-                return ecl_log1p_simple(x);
-        } else {
-  		float f = number_to_float(x);
-		if (f < -1) return ecl_log1p_simple(x);
-		return ecl_make_singlefloat(log1pf(number_to_float(x)));
-        }
+        float f = number_to_float(x);
+        if (f < -1) return ecl_log1p_simple(x);
+        return ecl_make_singlefloat(log1pf(number_to_float(x)));
 }
 
 static cl_object
@@ -222,6 +220,6 @@ ecl_log1p_complex(cl_object x)
 }
 
 MATH_DEF_DISPATCH1(log1p, @[si::log1p], @[number],
-                   ecl_log1p_rational, ecl_log1p_single_float,
-                   ecl_log1p_double_float, ecl_log1p_long_float,
+                   ecl_log1p_rational, ecl_log1p_simple, ecl_log1p_rational,
+                   ecl_log1p_single_float, ecl_log1p_double_float, ecl_log1p_long_float,
                    ecl_log1p_complex);
diff --git a/src/c/numbers/sin.d b/src/c/numbers/sin.d
index 21c43e996..f2099b3b7 100644
--- a/src/c/numbers/sin.d
+++ b/src/c/numbers/sin.d
@@ -70,6 +70,6 @@ ecl_sin_complex(cl_object x)
 }
 
 MATH_DEF_DISPATCH1(sin, @[sin], @[number],
-                   ecl_sin_rational, ecl_sin_single_float,
-                   ecl_sin_double_float, ecl_sin_long_float,
+                   ecl_sin_rational, ecl_sin_rational, ecl_sin_rational,
+                   ecl_sin_single_float, ecl_sin_double_float, ecl_sin_long_float,
                    ecl_sin_complex);
diff --git a/src/c/numbers/sinh.d b/src/c/numbers/sinh.d
index 11795fe01..40c89a1fd 100644
--- a/src/c/numbers/sinh.d
+++ b/src/c/numbers/sinh.d
@@ -71,6 +71,6 @@ ecl_sinh_complex(cl_object x)
 }
 
 MATH_DEF_DISPATCH1(sinh, @[sinh], @[number],
-                   ecl_sinh_rational, ecl_sinh_single_float,
-                   ecl_sinh_double_float, ecl_sinh_long_float,
+                   ecl_sinh_rational, ecl_sinh_rational, ecl_sinh_rational,
+                   ecl_sinh_single_float, ecl_sinh_double_float, ecl_sinh_long_float,
                    ecl_sinh_complex);
diff --git a/src/c/numbers/sqrt.d b/src/c/numbers/sqrt.d
index 00abb13c7..c95fbf024 100644
--- a/src/c/numbers/sqrt.d
+++ b/src/c/numbers/sqrt.d
@@ -84,6 +84,6 @@ ecl_sqrt_complex(cl_object x)
 }
 
 MATH_DEF_DISPATCH1(sqrt, @[sqrt], @[number],
-                   ecl_sqrt_rational, ecl_sqrt_single_float,
-                   ecl_sqrt_double_float, ecl_sqrt_long_float,
+                   ecl_sqrt_rational, ecl_sqrt_rational, ecl_sqrt_rational,
+                   ecl_sqrt_single_float, ecl_sqrt_double_float, ecl_sqrt_long_float,
                    ecl_sqrt_complex);
diff --git a/src/c/numbers/tan.d b/src/c/numbers/tan.d
index 4c0780b09..108027c8c 100644
--- a/src/c/numbers/tan.d
+++ b/src/c/numbers/tan.d
@@ -75,6 +75,6 @@ ecl_tan_complex(cl_object x)
 }
 
 MATH_DEF_DISPATCH1(tan, @[tan], @[number],
-                   ecl_tan_rational, ecl_tan_single_float,
-                   ecl_tan_double_float, ecl_tan_long_float,
+                   ecl_tan_rational, ecl_tan_rational, ecl_tan_rational,
+                   ecl_tan_single_float, ecl_tan_double_float, ecl_tan_long_float,
                    ecl_tan_complex);
diff --git a/src/c/numbers/tanh.d b/src/c/numbers/tanh.d
index f75c5538f..185330712 100644
--- a/src/c/numbers/tanh.d
+++ b/src/c/numbers/tanh.d
@@ -63,6 +63,6 @@ ecl_tanh_complex(cl_object x)
 }
 
 MATH_DEF_DISPATCH1(tanh, @[tanh], @[number],
-                   ecl_tanh_rational, ecl_tanh_single_float,
-                   ecl_tanh_double_float, ecl_tanh_long_float,
+                   ecl_tanh_rational, ecl_tanh_rational, ecl_tanh_rational,
+                   ecl_tanh_single_float, ecl_tanh_double_float, ecl_tanh_long_float,
                    ecl_tanh_complex);
diff --git a/src/h/impl/math_dispatch.h b/src/h/impl/math_dispatch.h
index 8954c9b13..0f338127a 100644
--- a/src/h/impl/math_dispatch.h
+++ b/src/h/impl/math_dispatch.h
@@ -25,7 +25,7 @@ typedef cl_object (*math_one_arg_fn)(cl_object);
 #else
 #define MATH_LONG_DOUBLE(opt)
 #endif
-#define MATH_DEF_DISPATCH1(name,id,type,rational,single_float,double_float,long_float,complex) \
+#define MATH_DEF_DISPATCH1(name,id,type,fix,big,ratio,single_float,double_float,long_float,complex) \
     static cl_object name##failed(cl_object x) {                        \
         FEwrong_type_only_arg(id, x, type);                             \
     }                                                                   \
@@ -33,7 +33,7 @@ typedef cl_object (*math_one_arg_fn)(cl_object);
         name##failed, /* t_start */                                     \
         name##failed, /* t_list */                                      \
         name##failed, /* t_character */                                 \
-        rational, rational, rational, /* t_fixnum, bignum, ratio */     \
+        fix, big, ratio, /* t_fixnum, bignum, ratio */                  \
         single_float, double_float, /* t_singlefloat, t_doublefloat */  \
         MATH_LONG_DOUBLE(long_float) /* t_longfloat, optional */        \
         complex };                                                      \