Move also cpu/ to bertos/ :-).

[bertos.git] / bertos / cpu / arm / hw / switch.h

diff --git a/bertos/cpu/arm/hw/switch.h b/bertos/cpu/arm/hw/switch.h
new file mode 100644 (file)
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+++ b/bertos/cpu/arm/hw/switch.h
@@ -0,0 +1,90 @@
+/**
+ * \file
+ * <!--
+ * This file is part of BeRTOS.
+ *
+ * Bertos is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ *
+ * As a special exception, you may use this file as part of a free software
+ * library without restriction.  Specifically, if other files instantiate
+ * templates or use macros or inline functions from this file, or you compile
+ * this file and link it with other files to produce an executable, this
+ * file does not by itself cause the resulting executable to be covered by
+ * the GNU General Public License.  This exception does not however
+ * invalidate any other reasons why the executable file might be covered by
+ * the GNU General Public License.
+ *
+ * Copyright 2008 Develer S.r.l. (http://www.develer.com/)
+ *
+ * -->
+ *
+ * \brief Kernel scheduler macros.
+ *
+ * \version $Id$
+ *
+ * \author Francesco Sacchi <batt@develer.com>
+ * \author Stefano Fedrigo <aleph@develer.com>
+ */
+
+#ifndef CPU_ARM_HW_SWITCH_H
+#define CPU_ARM_HW_SWITCH_H
+
+#include <kern/proc_p.h>
+
+/**
+ * Interrupt entry point.
+ * Needed because AT91 uses an Interrupt Controller with auto-vectoring.
+ */
+#define SCHEDULER_IRQ_ENTRY \
+       asm volatile("sub   lr, lr, #4          \n\t"  /* Adjust LR */ \
+                    "stmfd sp!, {r0}           \n\t"  /* Save r0 */ \
+                    "stmfd sp, {sp}^           \n\t"  /* Save user SP */ \
+                    "sub   sp, sp, #4          \n\t"  /* Decrement irq SP, writeback is illegal */ \
+                    "ldmfd sp!, {r0}           \n\t"  /* Restore user SP immedately in r0 */ \
+                    "stmfd r0!, {lr}           \n\t"  /* Store system LR in user stack */ \
+                    "stmfd r0, {r1-r12,lr}^    \n\t"  /* Store registers on user stack (user LR too) */ \
+                    "sub   r0, r0, #52         \n\t"  /* Decrement r0, writeback is illegal */ \
+                    "ldmfd sp!, {r1}           \n\t"  /* Restore r0 */ \
+                    "stmfd r0!, {r1}           \n\t"  /* Store r0 in user stack too */ \
+                    "mrs   r1, spsr            \n\t"  /* Save SPSR... */ \
+                    "stmfd r0!, {r1}           \n\t"  /*  ... in user stack */ \
+                    "ldr   r1, =CurrentProcess \n\t"  /* Load in r1 &CurrentProcess->stack */ \
+                    "ldr   r1, [r1, %0]        \n\t"  \
+                    "str   r0, [r1]            \n\t"  /* Store the process SP */ \
+                    "sub   fp, sp, #4          \n\t"  /* Store the process SP */ \
+                    : /* no output */ \
+                    : "n" (offsetof(Process, stack)) \
+       )
+
+
+#define SCHEDULER_IRQ_EXIT \
+       asm volatile("ldr   lr, =CurrentProcess \n\t"  /* Load &CurrentProcess->stack */ \
+                    "ldr   lr, [lr, %0]        \n\t"  \
+                    "ldr   lr, [lr]            \n\t"  /* Load current process SP */ \
+                    "ldr   r0, =0xFFFFF000     \n\t"  /* End of interrupt for AT91 */ \
+                    "str   r0, [r0, #0x130]    \n\t"  /* */ \
+                    "ldmfd lr!, {r0}           \n\t"  /* Pop status reg */ \
+                    "msr   spsr, r0            \n\t"  /* ... */ \
+                    "ldmfd lr, {r0-r12,lr}^    \n\t"  /* Restore user regs */ \
+                    "add   lr, lr, #56         \n\t"  /* 52 + irq link register (extracted below) */ \
+                    "stmfd sp!, {lr}           \n\t"  /* Push user stack pointer in irq stack */ \
+                    "ldmfd sp,  {sp}^          \n\t"  /* Restore user SP */ \
+                    "sub   sp, sp, #4          \n\t"  /* Align irq SP */ \
+                    "ldmdb lr, {pc}^           \n\t"  /* And return to user space (We use ldmdb cause lr is sp+4) */ \
+                    : /* no output */ \
+                    : "n" (offsetof(Process, stack))  \
+       )
+
+#endif /* CPU_ARM_HW_SWITCH_H */