started fixing bug #737001 (SDCC not clearing uninitialized variables) for the mcs51...

xdata initialization slightly shorter

git-svn-id: https://sdcc.svn.sourceforge.net/svnroot/sdcc/trunk/sdcc@3013 4a8a32a2-be11-0410-ad9d-d568d2c75423

diff --git a/src/mcs51/main.c b/src/mcs51/main.c
index 6d88a68d4152f0fb937d081c6e43f6633aedca35..8a8dc53b9ca809a776e9a69ee01da4715a1ca026 100644 (file)
--- a/src/mcs51/main.c
+++ b/src/mcs51/main.c
@@ -153,13 +153,33 @@ _mcs51_genIVT (FILE * of, symbol ** interrupts, int maxInterrupts)
   return FALSE;
 }
 
+/* Generate code to clear XSEG and idata memory. 
+   This clears XSEG, DSEG, BSEG, OSEG, SSEG */
+static void _mcs51_genRAMCLEAR (FILE * of) {
+  fprintf (of, ";      _mcs51_genRAMCLEAR() start\n");
+  fprintf (of, "       mov     r1,#l_XSEG\n");
+  fprintf (of, "       mov     a,r1\n");
+  fprintf (of, "       orl     a,#(l_XSEG >> 8)\n");
+  fprintf (of, "       jz      00005$\n");
+  fprintf (of, "       mov     r2,#((l_XSEG + 255) >> 8)\n");
+  fprintf (of, "       mov     dptr,#s_XSEG\n");
+  fprintf (of, "       clr     a\n");
+  fprintf (of, "00004$:        movx    @dptr,a\n");
+  fprintf (of, "       inc     dptr\n");
+  fprintf (of, "       djnz    r1,00004$\n");
+  fprintf (of, "       djnz    r2,00004$\n");
+  /* r1 is zero now. Clearing 256 byte assuming 128 byte devices don't mind */
+  fprintf (of, "00005$:        mov     @r1,a\n");   
+  fprintf (of, "       djnz    r1,00005$\n");
+  fprintf (of, ";      _mcs51_genRAMCLEAR() end\n");
+}
+
 /* Generate code to copy XINIT to XISEG */
 static void _mcs51_genXINIT (FILE * of) {
   fprintf (of, ";      _mcs51_genXINIT() start\n");
   fprintf (of, "       mov     r1,#l_XINIT\n");
-  fprintf (of, "       mov     r2,#(l_XINIT >> 8)\n");
   fprintf (of, "       mov     a,r1\n");
-  fprintf (of, "       orl     a,r2\n");
+  fprintf (of, "       orl     a,#(l_XINIT >> 8)\n");
   fprintf (of, "       jz      00003$\n");
   fprintf (of, "       mov     r2,#((l_XINIT+255) >> 8)\n");
   fprintf (of, "       mov     dptr,#s_XINIT\n");
@@ -177,6 +197,8 @@ static void _mcs51_genXINIT (FILE * of) {
   fprintf (of, "       mov     p2,#0xFF\n");
   fprintf (of, "00003$:\n");
   fprintf (of, ";      _mcs51_genXINIT() end\n");
+  
+  if (getenv("SDCC_GENRAMCLEAR")) _mcs51_genRAMCLEAR (of);
 }