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https://github.com/cccriscv/mini-riscv-os.git
synced 2025-11-16 12:34:33 +00:00
62810c1a83
Hey there, I implemented risc-v in fpga and try to port your mini-os to my fpga. 02_ContextSwitch did not work correctly, because the stackpointer is not word alligned after context switch. Changing uint8_t to word size (32 bit) solved the problem, because &task0_stack[STACK_SIZE-1] should be the last word of the stack, instead of the last byte of the stack. Some hardware may ignore the two least significant bits of address when accessing a 32 bit word. So uint8_t might work also.
25 lines
429 B
C
25 lines
429 B
C
#include "os.h"
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#define STACK_SIZE 1024
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reg_t task0_stack[STACK_SIZE];
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struct context ctx_os;
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struct context ctx_task;
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extern void sys_switch();
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void user_task0(void)
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{
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lib_puts("Task0: Context Switch Success !\n");
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while (1) {} // stop here.
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}
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int os_main(void)
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{
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lib_puts("OS start\n");
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ctx_task.ra = (reg_t) user_task0;
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ctx_task.sp = (reg_t) &task0_stack[STACK_SIZE-1];
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sys_switch(&ctx_os, &ctx_task);
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return 0;
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}
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