Enable and initialize VFP on imx31. VFP state is not saved on thread change, and it is initialized for scalar operations, rounding toward zero, with exception/error handling and "correct" handling of NaN and denormal values disabled. In this mode it should still be usable for integer divisions (by casting operands to double and result to int or unsigned).

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@24129 a1c6a512-1295-4272-9138-f99709370657

firmware/target/arm/imx31/crt0.S

@@ -292,6 +292,25 @@ remap_end:
 
     /* Switch back to supervisor mode */
     msr     cpsr_c, #0xd3
+
+#ifndef BOOTLOADER
+    /* Enable access to VFP */
+    mrc     p15, 0, r3, c1, c0, 2
+    orr     r3, r3, #0xf00000
+    mcr     p15, 0, r3, c1, c0, 2
+    
+    /* Enable VFP */
+    mrc     p10, 7, r3, c8, c0, 0
+    orr     r3, r3, #1<<30
+    mcr     p10, 7, r3, c8, c0, 0
+
+    /* Disable exceptions, enable default NaN, flush-to-zero, round toward 0 */
+    mrc     p10, 7, r3, c1, c0, 0
+    orr     r3, r3, #15<<22
+    bic     r3, r3, #31<<8
+    mcr     p10, 7, r3, c1, c0, 0
+#endif
+    
     bl      main
 
 #ifdef BOOTLOADER