* device/lib/_strlen.c: assembler version for mcs51

[fw/sdcc] / device / lib / _strlen.c

diff --git a/device/lib/_strlen.c b/device/lib/_strlen.c
index 6d0e9acdaba288f7a8725580d0aa540f88d0ce9a..e2cbf4280475cc2d32eca004cd93361f74ff89b5 100644 (file)
--- a/device/lib/_strlen.c
+++ b/device/lib/_strlen.c
@@ -1,7 +1,8 @@
 /*-------------------------------------------------------------------------
-  _strcpy.c - part of string library functions
+  _strlen.c - part of string library functions
 
              Written By -  Sandeep Dutta . sandeep.dutta@usa.net (1999)
+                           mcs51 assembler by Frieder Ferlemann (2007)
 
    This library is free software; you can redistribute it and/or modify it
    under the terms of the GNU Library General Public License as published by the
@@ -21,14 +22,58 @@
    You are forbidden to forbid anyone else to use, share and improve
    what you give them.   Help stamp out software-hoarding!
 -------------------------------------------------------------------------*/
-#include "string.h"
 
-int strlen ( char * str ) 
-{
-       register int i = 0 ;
+#if (!defined (SDCC_mcs51))
 
-       while (*str++) 
-               i++ ;
+  /* Generic routine first */
+  int strlen ( char * str )
+  {
+    register int i = 0 ;
 
-       return i;
-}
+    while (*str++)
+      i++ ;
+
+    return i;
+  }
+
+#else
+
+  /* Assembler version for mcs51 */
+  int strlen ( char * str ) __naked
+  {
+    str;     /* hush the compiler */
+
+    __asm
+      ; dptr holds pointer
+      ; b holds pointer memspace
+      ;
+
+      ; char *ptr = str:
+      mov     r2,dpl
+      mov     r3,dph
+      ;
+
+      ; while ( *ptr ) ptr++;
+    L00101$:
+      lcall   __gptrget
+      jz      L00102$
+      inc     dptr
+      sjmp    L00101$
+      ;
+
+    L00102$:
+      ; return ptr - str;
+      clr     c
+      mov     a,dpl
+      subb    a,r2
+      mov     dpl,a
+      ;
+      mov     a,dph
+      subb    a,r3
+      mov     dph,a
+      ;
+      ret
+    __endasm;
+  }
+
+#endif