Interrupts setup

.gitignore

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+temp_build/build/
+temp_build/s-mode/
+temp_build/u-mode/

temp_build/common/pt_interrupt.S

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+
+/*
+.align 4
+.global vector_table
+.option push
+.option norvc
+vector_table:
+    j exception_handler     // exceptions jump to cause 0
+    j ssip_handler          // 1
+    j unreachable_handler   // 2
+    j msip_handler          // 3
+
+    j unreachable_handler   // 4 
+    j stip_handler          // 5
+    j unreachable_handler   // 6
+    j mtip_handler          // 7
+
+    j unreachable_handler   // 8
+    j seip_handler          // 9
+    j unreachable_handler   // 10
+    j meip_handler          // 11
+
+    j unreachable_handler   // 12
+    j lcofip_handler        // 13
+    j unreachable_handler   // 14
+    j unreachable_handler   // 15
+    // end of standard interrupts
+.option pop
+*/

temp_build/interrupts-exceptions/proc.h

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+/* proc.h */
+
+#ifndef _PROC_H_
+#define _PROC_H_
+
+#define NPROC 64   /* max number of processes */
+
+/* Process states */
+#define PR_FREE   0
+#define PR_READY  1
+#define PR_CURR   2
+#define PR_SLEEP  3
+
+struct procent {
+    uint16  prstate;
+    pri16   prprio; //process priority
+    char    *prstkptr; //stack pointer
+    char    *prstkbase; //base of runtime stack
+    uint32  prstklen; //stack length in bytes
+    //char    prname[PNMLEN] //process name
+    sid32   prsem; //semaphore for process
+    pid32   prparent; //ID of creating process
+    //umsg    prmsg; //message sent to this process
+    //bool8   prhasmsg; //Nonzero iff msg is valid
+    //int16   prdesc[NDESC]; //device descriptors for process
+};
+
+extern struct procent proctab[NPROC];
+
+#endif

temp_build/interrupts-exceptions/process_table.c

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+
+#include <stdint.h>
+#include "csr.h"
+#include "utility.h"
+#include "format.h"
+
+#define QUANTUM 2;
+
+int queue[5] = {1, 2, 3, 4, 5};
+int index = 0;
+uint64_t volatile time_remaining = QUANTUM;
+
+void reschedule_function() {
+    index++;
+    time_remaining = QUANTUM;
+    print("Index increments. Index at %d. ", index);
+}
+
+void set_timer(uint64_t value) {
+    *MTIMECMP = *MTIME + value;
+}
+
+void meip_handler() {
+    print("meip handling....");
+    *EXT_CLEAR = 0x1; // writing anything simulates clearing interrupt
+    CSRW("mie", 0x088);
+    //index++;
+    print("Handled. ");
+}
+
+void mtip_handler() {
+    print("mtip handling...."); 
+    time_remaining -= 1;
+    if (time_remaining <= 0) {	    
+    	reschedule_function();
+    }
+    set_timer(1000);
+    print("Handled. "); 
+}
+
+void msip_handler() {
+    print("msip handling....");
+    *MSIP = 0x0; // writing 0 clears this
+    //index++;
+    print("Handled. ", index);
+}
+
+int main() {
+    *MTIMECMPH = 0x00;
+    *MTIMECMP  = 0xFF;
+
+    setup_interrupt_m_vectored(vector_table, IE_MTIE | IE_MSIE | IE_MEIE);
+    enable_interrupts_m();
+
+    *MSIP = 1;
+    *EXT_SET = 1;
+
+    while (*MTIME < 0xFFFF);    
+
+    return 0;
+}