Fix FLNP1 calculation (#160)

Was log(x)+1 Now log(x+1) Fixes #155
philburk · Mar 28, 2024 · ce91977 · ce91977
1 parent 8da2f09
commit ce91977
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Showing 2 changed files with 2 additions and 1 deletion.
diff --git a/csrc/pf_float.h b/csrc/pf_float.h
@@ -36,6 +36,7 @@ typedef double PF_FLOAT;
 #define fp_floor  floor
 #define fp_log    log
 #define fp_log10  log10
+#define fp_log1p  log1p
 #define fp_pow    pow
 #define fp_sin    sin
 #define fp_sinh   sinh

diff --git a/csrc/pfinnrfp.h b/csrc/pfinnrfp.h
@@ -301,7 +301,7 @@
         break;
 
     case ID_FP_FLNP1: /* ( -- ) ( F: r1 -- r2 ) */
-        FP_TOS = (PF_FLOAT) (fp_log(FP_TOS) + 1.0);
+        FP_TOS = (PF_FLOAT) fp_log1p(FP_TOS); /* log(x+1) */
         break;
 
     case ID_FP_FLOG: /* ( -- ) ( F: r1 -- r2 ) */