diff options
Diffstat (limited to 'nuttx/arch/arm/src/lm3s/lm3s_vectors.S')
| -rw-r--r-- | nuttx/arch/arm/src/lm3s/lm3s_vectors.S | 98 |
1 files changed, 97 insertions, 1 deletions
diff --git a/nuttx/arch/arm/src/lm3s/lm3s_vectors.S b/nuttx/arch/arm/src/lm3s/lm3s_vectors.S index 1d10e9021c..3f196ae921 100644 --- a/nuttx/arch/arm/src/lm3s/lm3s_vectors.S +++ b/nuttx/arch/arm/src/lm3s/lm3s_vectors.S @@ -68,9 +68,16 @@ * Macros
************************************************************************************/
+/* On entry into an IRQ, the hardware automatically saves the xPSR, PC, LR, R12, R0-R3
+ * registers on the stack, then branches to an instantantiation of the following
+ * macro. This macro simply loads the IRQ number into R0, then jumps to the common
+ * IRQ handling logic.
+ */
+
.macro HANDLER, label, irqno
\label:
-#warning "Missing logic"
+ mov r0, \irqno
+ br lm3s_irqcommon
.endm
/************************************************************************************
@@ -171,6 +178,8 @@ lm3s_vectors: .text
.thumb_func
+ .type handlers, function
+handlers:
HANDLER lm3s_reserved, LMSB_IRQ_RESERVED /* Unexpected/reserved vector */
HANDLER lm3s_nmi, LMSB_IRQ_NMI /* Vector 2: Non-Maskable Interrupt (NMI) */
HANDLER lm3s_hardfault, LMSB_IRQ_HARDFAULT /* Vector 3: Hard fault */
@@ -220,6 +229,93 @@ lm3s_vectors: # error "Vectors not specified for this LM3S chip"
#endif
+
+/* Common IRQ handling logic. On entry here, the stack is like the following:
+ *
+ * REG_XPSR
+ * REG_R15
+ * REG_R14
+ * REG_R12
+ * REG_R3
+ * REG_R2
+ * REG_R1
+ * PSP->REG_R0
+ *
+ * and R0 contains the IRQ number
+ */
+
+lm3s_irqcommon:
+ /* Complete the context save */
+
+ mrs r1, psp /* R1=The process stack pointer */
+ mov r3, r1 /* R3=Copy of the process stack pointer */
+ add r3, #HW_XCPT_SIZE /* R3=PSP before the interrupt was taken */
+ stmdb r1!, {r3-r11} /* Save the remaining registers plus the SP value */
+
+ /* Disable interrupts, select the stack to use for interrupt handling
+ * and call up_doirq to handle the interrupt
+ */
+
+ cpsid i /* Disable further interrupts */
+
+ /* If CONFIG_ARCH_INTERRUPTSTACK is defined, we will use a special interrupt
+ * stack pointer. The way that this is done here prohibits nested interrupts!
+ * Otherwise, we will re-use the process stack for interrupt level processing.
+ */
+
+#ifdef CONFIG_ARCH_INTERRUPTSTACK
+ ld sp, #up_interruptstack_base
+#else
+ mov sp, r1 /* Use the process stack pointer */
+#endif
+ stmdb sp!, {r1, r14} /* Save the process SP and the return LR */
+ bl up_doirq /* R0=IRQ, R1=register save */
+ ldmia sp!, {r1, r14} /* Recover the process SP and the return LR */
+
+ /* On return from up_doirq, R0 will hold a pointer to register context
+ * array to use for the interrupt return. If that return value is the same
+ * as current stack pointer, then things are relatively easy.
+ */
+
+ cmp r0, r1
+ beq 1f /* Branch if no context switch */
+
+ /* We are returning from a context switch. This is different because in this
+ * case, the register save structure does not lie on the stack but, rather,
+ * is within a TCB structure. We'll have to copy some values to the stack.
+ */
+
+ add r1, r0, #(XCPTCONTEXT_SIZE-4) /* r2=offset HW save area */
+ ldmia r1, {r4, r11} /* Eight registers in HW save area */
+ ldr r1, [r0, #(4*REG_SP)] /* R1=Value of SP before interrupt */
+ stmdb r1!, {r4, r11} /* Eight registers in HW save area */
+ mov psp, r1 /* New PSP */
+
+ /* We simply need to "unwind" the same stack frame that we created */
+1:
+ cpsie i /* Restore interrupts */
+ stmdb r0!, {r3-r11} /* Recover R4-R11 (R3 does not have the correct value yet) * the remaining registers plus the SP value */
+ bx r14 /* And return */
+ .size handler, .-handlers
+
+/************************************************************************************
+ * Name: up_interruptstack/g_userstack
+ *
+ * Description:
+ * Shouldn't happen
+ *
+ ************************************************************************************/
+
+#if CONFIG_ARCH_INTERRUPTSTACK > 3
+ .bss
+ .align 4
+up_interruptstack:
+ .skip ((CONFIG_ARCH_INTERRUPTSTACK & ~3) - 4)
+up_interruptstack_base:
+ .skip 4
+ .size up_interruptstack, .-up_interruptstack
+#endif
+
/************************************************************************************
* .rodata
************************************************************************************/
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