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Diffstat (limited to 'c/src/lib/libbsp/powerpc/mpc8260ads/irq/irq_asm.S')
-rw-r--r--c/src/lib/libbsp/powerpc/mpc8260ads/irq/irq_asm.S28
1 files changed, 24 insertions, 4 deletions
diff --git a/c/src/lib/libbsp/powerpc/mpc8260ads/irq/irq_asm.S b/c/src/lib/libbsp/powerpc/mpc8260ads/irq/irq_asm.S
index f38d3dad83..e42a7060e3 100644
--- a/c/src/lib/libbsp/powerpc/mpc8260ads/irq/irq_asm.S
+++ b/c/src/lib/libbsp/powerpc/mpc8260ads/irq/irq_asm.S
@@ -12,6 +12,9 @@
* Modifications to store nesting level in global _ISR_Nest_level
* variable instead of SPRG0. Andy Dachs <a.dachs@sstl.co.uk>
*
+ * Till Straumann <strauman@slac.stanford.edu>, 2005/4:
+ * - DONT enable FP across user ISR since fpregs are never saved!!
+ *
* $Id$
*/
@@ -93,11 +96,7 @@ SYM (shared_raw_irq_code_entry):
* also, on CPUs with FP, enable FP so that FP context can be
* saved and restored (using FP instructions)
*/
-#if (PPC_HAS_FPU == 0)
ori r3, r3, MSR_RI /*| MSR_IR | MSR_DR*/
-#else
- ori r3, r3, MSR_RI | /*MSR_IR | MSR_DR |*/ MSR_FP
-#endif
mtmsr r3
SYNC
@@ -301,6 +300,27 @@ nested:
rfi
switch:
+#if ( PPC_HAS_FPU != 0 )
+#if ! defined( CPU_USE_DEFERRED_FP_SWITCH )
+#error missing include file???
+#endif
+ mfmsr r4
+#if ( CPU_USE_DEFERRED_FP_SWITCH == TRUE )
+ /* if the executing thread has FP enabled propagate
+ * this now so _Thread_Dispatch can save/restore the FPREGS
+ * NOTE: it is *crucial* to disable the FPU across the
+ * user ISR [independent of using the 'deferred'
+ * strategy or not]. We don't save FP regs across
+ * the user ISR and hence we prefer an exception to
+ * be raised rather than experiencing corruption.
+ */
+ lwz r3, SRR1_FRAME_OFFSET(r1)
+ rlwimi r4, r3, 0, 18, 18 /* MSR_FP */
+#else
+ ori r4, r4, MSR_FP
+#endif
+ mtmsr r4
+#endif
bl SYM (_Thread_Dispatch)
easy_exit: