75 lines
2 KiB
ArmAsm
75 lines
2 KiB
ArmAsm
#include "AT91RM9200_inc.h"
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#define ARM_MODE_USER 0x10
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#define ARM_MODE_FIQ 0x11
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#define ARM_MODE_IRQ 0x12
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#define ARM_MODE_SVC 0x13
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#define ARM_MODE_ABORT 0x17
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#define ARM_MODE_UNDEF 0x1B
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#define ARM_MODE_SYS 0x1F
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#define I_BIT 0x80
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#define F_BIT 0x40
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#define T_BIT 0x20
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/* -----------------------------------------------------------------------------
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AT91F_ASM_SPI_Handler
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---------------------
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Handler called by the AIC
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Save context
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Call C handler
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Restore context
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----------------------------------------------------------------------------- */
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.global AT91F_ST_ASM_HANDLER
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AT91F_ST_ASM_HANDLER:
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/* Adjust and save LR_irq in IRQ stack */
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sub r14, r14, #4
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stmfd sp!, {r14}
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/* Write in the IVR to support Protect Mode
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No effect in Normal Mode
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De-assert the NIRQ and clear the source in Protect Mode */
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ldr r14, =AT91C_BASE_AIC
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str r14, [r14, #AIC_IVR]
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/* Save SPSR and r0 in IRQ stack */
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mrs r14, SPSR
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stmfd sp!, {r0, r14}
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/* Enable Interrupt and Switch in SYS Mode */
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mrs r0, CPSR
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bic r0, r0, #I_BIT
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orr r0, r0, #ARM_MODE_SYS
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msr CPSR_c, r0
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/* Save scratch/used registers and LR in User Stack */
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stmfd sp!, { r1-r3, r12, r14}
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ldr r1, =AT91F_ST_HANDLER
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mov r14, pc
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bx r1
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/* Restore scratch/used registers and LR from User Stack */
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ldmia sp!, { r1-r3, r12, r14}
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/* Disable Interrupt and switch back in IRQ mode */
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mrs r0, CPSR
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bic r0, r0, #ARM_MODE_SYS
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orr r0, r0, #I_BIT | ARM_MODE_IRQ
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msr CPSR_c, r0
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/* Mark the End of Interrupt on the AIC */
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ldr r0, =AT91C_BASE_AIC
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str r0, [r0, #AIC_EOICR]
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/* Restore SPSR_irq and r0 from IRQ stack */
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ldmia sp!, {r0, r14}
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msr SPSR_cxsf, r14
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/* Restore adjusted LR_irq from IRQ stack directly in the PC */
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ldmia sp!, {pc}^
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