122 lines
1.9 KiB
ArmAsm
Executable File
122 lines
1.9 KiB
ArmAsm
Executable File
.syntax unified
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@ .cpu cortex-m3
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.thumb
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.global syscall_handler_get
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/**
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* @brief syscall结束时到这儿
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*/
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.type syscall_exit, %function
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syscall_exit:
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svc 1
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b .
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/**
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* void syscall_ret_user(int ret_val);
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* @brief 回到用户模式
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*/
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.type syscall_ret_user, %function
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syscall_ret_user:
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//存放返回值
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//还原msp的值
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mrs r0, msp
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#ifdef MKRTOS_USE_FPU
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// 如果支持浮点，则里则要把惰性浮点得位置留查出来
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TST lr, #0x10
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IT eq
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addeq r0,r0,#0x48
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#endif
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add r0, #0x20
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ldmfd r0!,{r4-r11}
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msr msp,r0
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pop {r0,r1,r2,lr}
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msr CONTROL, r1
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CPSIE I
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bx lr
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/**
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* void SVC_Handler(void);
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* @brief
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*/
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.global SVC_Handler
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.type SVC_Handler, %function
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SVC_Handler:
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CPSID I
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TST.W LR, #4
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ITE EQ
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MRSEQ R1, MSP
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MRSNE R1, PSP
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//获得svc的调用号
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LDR R2, [R1, #24]
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LDRB R2, [R2, #-2]
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cmp r2,#128
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beq SYS_CALL
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cmp r2,#1
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beq TO_USER
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cmp r2,#2
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// beq enter_fchannel
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// cmp r2,#3
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// beq exit_fchannel
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b TO_END
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TO_USER:
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B syscall_ret_user
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SYS_CALL:
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//获取堆栈地址
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mov r0,r1
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//放入之前的栈地址
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mrs r1,CONTROL
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push {r0,r1,r2,lr}
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//svc 128
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mov r1, r7
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//获得需要调用的syscall函数的地址
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push {r0-r2,lr}
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blx syscall_handler_get
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mov r3,r0
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pop {r0-r2,lr}
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//r4-r11 压入到内核栈中
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stmfd sp!,{r4-r11}
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//压入到用户栈中
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stmfd r0,{r4-r11}
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#ifdef MKRTOS_USE_FPU
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// 如果支持浮点，则里则要把惰性浮点得位置留查出来
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TST lr, #0x10
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IT eq
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subeq sp,sp,#0x48
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#endif
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//取出PSR PC LR R12 R3 R2 R1 R0
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ldmfd r0,{r4-r11}
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//压入到内核栈中
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stmfd sp!,{r4-r11}
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//取出lr与pc放到栈中
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mov r0,sp
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ldr r2, =syscall_exit
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//lr
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str r2, [r0, #20]
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//pc
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str r3, [r0, #24]
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ldr r3, =0x01000000
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str r3, [r0, #28]
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//重新设置control
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mrs r0, CONTROL
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bic r0, r0, #0x03
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msr CONTROL, r0
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dsb
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isb
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orr lr, lr, #0x08
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bic lr, lr, #0x04
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CPSIE I
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bx lr
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TO_END:
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CPSIE I
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bx lr
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