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Project/Src/rt-thread/libcpu/mips/loongson_1c/context_gcc.S

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+/*
+ * File      : context_gcc.S
+ * This file is part of RT-Thread RTOS
+ * COPYRIGHT (C) 2006 - 2011, RT-Thread Development Team
+ *
+ * The license and distribution terms for this file may be
+ * found in the file LICENSE in this distribution or at
+ * http://www.rt-thread.org/license/LICENSE
+ *
+ * Change Logs:
+ * Date           Author       Notes
+ * 2010-05-17     swkyer       first version
+ * 2010-09-11     bernard      port to Loongson SoC3210
+ * 2011-08-08     lgnq         port to Loongson LS1B
+ */
+
+#include "../common/mips.inc"
+#include "../common/stackframe.h"
+#include "stackframe_fpu.h"
+
+    .section ".text", "ax"
+    .set noreorder
+
+/*
+ * rt_base_t rt_hw_interrupt_disable()
+ */
+    .globl rt_hw_interrupt_disable
+rt_hw_interrupt_disable:
+    mfc0    v0, CP0_STATUS
+    and     v1, v0, 0xfffffffe
+    mtc0    v1, CP0_STATUS
+    jr      ra
+    nop
+
+/*
+ * void rt_hw_interrupt_enable(rt_base_t level)
+ */
+    .globl rt_hw_interrupt_enable
+rt_hw_interrupt_enable:
+    ori     a0, 0x00000800   
+    mtc0    a0, CP0_STATUS
+    ehb
+    mfc0    v0, CP0_CAUSE
+    ehb
+    or      v1, v0, 0x800000                 //EBASE + 0x200                                                                                                 
+    mtc0    v1, CP0_CAUSE
+    ehb
+    jr      ra
+    nop
+
+/*
+ * void rt_hw_context_switch(rt_uint32 from, rt_uint32 to)
+ * a0 --> from
+ * a1 --> to
+ */
+    .globl rt_hw_context_switch
+rt_hw_context_switch:
+    mtc0    ra, CP0_EPC
+    SAVE_ALL
+    SAVE_FPU
+
+    sw      sp, 0(a0)       /* store sp in preempted tasks TCB */
+    lw      sp, 0(a1)       /* get new task stack pointer */
+
+    RESTORE_FPU
+    RESTORE_ALL_AND_RET
+
+/*
+ * void rt_hw_context_switch_to(rt_uint32 to)/*
+ * a0 --> to
+ */
+    .globl rt_hw_context_switch_to
+rt_hw_context_switch_to:
+    lw      sp, 0(a0)       /* get new task stack pointer */
+
+    RESTORE_FPU
+    RESTORE_ALL_AND_RET
+
+/*
+ * void rt_hw_context_switch_interrupt(rt_uint32 from, rt_uint32 to)/*
+ */
+    .globl rt_thread_switch_interrupt_flag
+    .globl rt_interrupt_from_thread
+    .globl rt_interrupt_to_thread
+    .globl rt_hw_context_switch_interrupt
+rt_hw_context_switch_interrupt:
+    la      t0, rt_thread_switch_interrupt_flag
+    lw      t1, 0(t0)
+    nop
+    bnez    t1, _reswitch
+    nop
+    li      t1, 0x01                       /* set rt_thread_switch_interrupt_flag to 1 */
+    sw      t1, 0(t0)
+    la      t0, rt_interrupt_from_thread   /* set rt_interrupt_from_thread */
+    sw      a0, 0(t0)
+_reswitch:
+    la      t0, rt_interrupt_to_thread     /* set rt_interrupt_to_thread */
+    sw      a1, 0(t0)
+    jr      ra
+    nop
+
+/*
+ * void rt_hw_context_switch_interrupt_do(rt_base_t flag)
+ */
+    .globl rt_interrupt_enter
+    .globl rt_interrupt_leave
+    .globl mips_irq_handle
+mips_irq_handle:
+    SAVE_ALL
+    SAVE_FPU
+
+    mfc0    t0, CP0_CAUSE
+    and     t1, t0, 0xff
+	bnez	t1, spurious_interrupt		/* check exception */
+	nop
+
+	/* let k0 keep the current context sp */
+    move    k0, sp 
+    /* switch to kernel stack */
+    li      sp, SYSTEM_STACK
+
+    jal     rt_interrupt_enter
+    nop
+    jal     rt_interrupt_dispatch
+    nop
+    jal     rt_interrupt_leave
+    nop
+
+    /* switch sp back to thread's context */
+    move    sp, k0
+
+    /*
+     * if rt_thread_switch_interrupt_flag set, jump to
+     * rt_hw_context_switch_interrupt_do and don't return
+     */
+    la      k0, rt_thread_switch_interrupt_flag
+    lw      k1, 0(k0)
+    beqz    k1, spurious_interrupt
+    nop
+    sw      zero, 0(k0)                     /* clear flag */
+	nop
+
+    /*
+     * switch to the new thread
+     */
+    la      k0, rt_interrupt_from_thread
+    lw      k1, 0(k0)
+    nop
+    sw      sp, 0(k1)                       /* store sp in preempted tasks's TCB */
+
+    la      k0, rt_interrupt_to_thread
+    lw      k1, 0(k0)
+    nop
+    lw      sp, 0(k1)                       /* get new task's stack pointer */
+    j       spurious_interrupt
+    nop
+
+spurious_interrupt:
+    RESTORE_FPU
+    RESTORE_ALL_AND_RET
+
+    .set reorder