From 2da00e7daae9a39654a70317783d865cd6bff70d Mon Sep 17 00:00:00 2001
From: mrdudz <mrdudz@users.noreply.github.com>
Date: Mon, 28 Aug 2023 02:01:56 +0200
Subject: [PATCH] fix output for negative numbers

---
 libsrc/float/softfloat/softloat-ftostr.c | 73 +++++++++++++++++++-----
 1 file changed, 59 insertions(+), 14 deletions(-)

diff --git a/libsrc/float/softfloat/softloat-ftostr.c b/libsrc/float/softfloat/softloat-ftostr.c
index 203a2c21d..2479005e3 100644
--- a/libsrc/float/softfloat/softloat-ftostr.c
+++ b/libsrc/float/softfloat/softloat-ftostr.c
@@ -2,6 +2,10 @@
 #include <stdlib.h>
 #include <stdio.h>
 
+//#define DEBUG_VALUE
+
+// This is really a terrible function that should get completely rewritten and
+// tested by someone who knows what he is doing =P
 char *_ftostr(char *buffer, float f) {
     signed long intpart;
     float fracpart;
@@ -12,42 +16,83 @@ char *_ftostr(char *buffer, float f) {
 
     is_negative = (raw_value & 0x80000000) ? 1 : 0;     // very hacky indeed
 
-    intpart = (signed long)(f);
+    if (!is_negative) {
+        intpart = (signed long)(f);
+    } else {
+        intpart = (signed long)(f);
+        intpart = -intpart;
+    }
 
     f2 = intpart;
+#if 0
+    if (!is_negative) {
+        if (f2 > f) {
+            if (intpart > 0) {
+                --intpart;
+            }
+        }
+    } else {
+        if (f2 > f) {
+            if (intpart > 0) {
+                --intpart;
+            }
+        }
+//                ++intpart;
+    }
 
-    if (f2 > f) {
-        if (intpart > 0) {
-            --intpart;
+    if (!is_negative) {
+        if (intpart < 0) {
+            intpart *= -1;
+        }
+    } else {
+        if (intpart < 0) {
+            intpart *= -1;
         }
     }
-
-    if (intpart < 0) {
-        intpart *= -1;
-    }
-
+#endif
     f2 = intpart;
-    fracpart = f - f2;
+    if (!is_negative) {
+        fracpart = f - f2;
+    } else {
+        fracpart = (-f) - f2;
+    }
 
     f1 = 10000.0f;
 
     f1 = f1 * fracpart;
 
     n0 = (signed long)f1;
+#if 0
+    // caution: make sure fracpart can never be negative
     if (n0 < 0) {
         n0 *= -1;
     }
+#endif
 //    printf("n0:%ld\n",n0);
+#ifdef DEBUG_VALUE
     if (n0 >= 1000) {
         sprintf(buffer, "<0x%08lx:%s%ld.%ld>", raw_value, is_negative ? "-" : "", intpart, n0);
     } else if (n0 >= 100) {
-        sprintf(buffer, "<0x%08lx:%s%ld.0%ld>", *((unsigned long*)(&f)), is_negative ? "-" : "", intpart, n0);
+        sprintf(buffer, "<0x%08lx:%s%ld.0%ld>", raw_value, is_negative ? "-" : "", intpart, n0);
     } else if (n0 >= 10) {
-        sprintf(buffer, "<0x%08lx:%s%ld.00%ld>", *((unsigned long*)(&f)), is_negative ? "-" : "", intpart, n0);
+        sprintf(buffer, "<0x%08lx:%s%ld.00%ld>", raw_value, is_negative ? "-" : "", intpart, n0);
     } else if (n0 >= 1) {
-        sprintf(buffer, "<0x%08lx:%s%ld.000%ld>", *((unsigned long*)(&f)), is_negative ? "-" : "", intpart, n0);
+        sprintf(buffer, "<0x%08lx:%s%ld.000%ld>", raw_value, is_negative ? "-" : "", intpart, n0);
     } else {
-        sprintf(buffer, "<0x%08lx:%s%ld.0000%ld>", *((unsigned long*)(&f)), is_negative ? "-" : "", intpart, n0);
+        sprintf(buffer, "<0x%08lx:%s%ld.0000>", raw_value, is_negative ? "-" : "", intpart);
     }
+#else
+    if (n0 >= 1000) {
+        sprintf(buffer, "%s%ld.%ld", is_negative ? "-" : "", intpart, n0);
+    } else if (n0 >= 100) {
+        sprintf(buffer, "%s%ld.0%ld", is_negative ? "-" : "", intpart, n0);
+    } else if (n0 >= 10) {
+        sprintf(buffer, "%s%ld.00%ld", is_negative ? "-" : "", intpart, n0);
+    } else if (n0 >= 1) {
+        sprintf(buffer, "%s%ld.000%ld", is_negative ? "-" : "", intpart, n0);
+    } else {
+        sprintf(buffer, "%s%ld.0000", is_negative ? "-" : "", intpart);
+    }
+#endif
     return &buffer[0];
 }