41 lines
888 B
ArmAsm
41 lines
888 B
ArmAsm
.text
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.thumb
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.syntax unified
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.align 2
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.global _start
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_start:
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cpsid i
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//LPTMR0 interrupt stop
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ldr r0, =0x4102e000
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eor r1, r1, r1
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str r1, [r0]
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//M4 RTOS loader
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ldr r0, =0x1FFD2000 //M4 SRAM start addr
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ldr r1, =0x67400000 //M4 RTOS preload addr
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ldr r2, =0 //increment register
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ldr r4, [r1, #-4] //M4 RTOS size
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loop:
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ldr r3, [r1, r2] //load from dram
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str r3, [r0, r2] //store to sram
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add r2, #4 //increment
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cmp r2, r4 //does copy end?
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ble loop
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//return address override
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mrs r4, psp
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adr r5, jumper
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orr r5, r5, #1
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str r5, [r4,#24]
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bx lr //exit interrupt handler
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jumper: //M4 RTOS image jumper
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mrs r0, control
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bic r0, #2
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msr control, r0
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isb
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ldr r0, =0x1ffd2000 //M4 RTOS image head addr
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ldr r1, [r0] //initial stack addr
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mov sp, r1
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ldr r2, [r0,#4] //reset vector
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bx r2
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