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https://github.com/cccriscv/mini-riscv-os.git
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54 lines
1.1 KiB
C
54 lines
1.1 KiB
C
#include "os.h"
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extern void trap_vector();
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void trap_init()
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{
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// set the machine-mode trap handler.
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w_mtvec((reg_t)trap_vector);
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// enable machine-mode interrupts.
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w_mstatus(r_mstatus() | MSTATUS_MIE);
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}
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reg_t trap_handler(reg_t epc, reg_t cause)
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{
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reg_t return_pc = epc;
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reg_t cause_code = cause & 0xfff;
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if (cause & 0x80000000)
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{
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/* Asynchronous trap - interrupt */
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switch (cause_code)
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{
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case 3:
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lib_puts("software interruption!\n");
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break;
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case 7:
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lib_puts("timer interruption!\n");
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// disable machine-mode timer interrupts.
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w_mie(~((~r_mie()) | (1 << 7)));
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timer_handler();
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return_pc = (reg_t)&os_kernel;
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// enable machine-mode timer interrupts.
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w_mie(r_mie() | MIE_MTIE);
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break;
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case 11:
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lib_puts("external interruption!\n");
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break;
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default:
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lib_puts("unknown async exception!\n");
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break;
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}
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}
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else
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{
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/* Synchronous trap - exception */
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lib_puts("Sync exceptions!\n");
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while (1)
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{
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/* code */
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}
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}
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return return_pc;
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}
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