feat(syscall): implement exit

Author: EmbroiderSnow

sim/include/syscall.h

@@ -0,0 +1,11 @@
+#ifndef SYSCALL_H
+#define SYSCALL_H
+
+#include <decode.h>
+
+#define SYSCALL_EXIT 93
+#define SYSCALL_WRITE 64
+
+void handle_syscall(Decode *s);
+
+#endif

sim/src/syscall.c

@@ -1,14 +1,15 @@
 #include <cpu.h>
-#include <trap.h>
+#include <include/syscall.h>
 #include <decode.h>
+#include <stdio.h>
 
 extern CPU_state cpu;
 
 void handle_syscall(Decode *s) {
     uint64_t syscall_no = cpu.reg[17]; // a7 register
     switch (syscall_no) {
         case SYSCALL_EXIT:
-            Log("Syscall: exit with code %lu", cpu.reg[10]); // a0 register
+            printf("Syscall: exit with code %lu\n", cpu.reg[10]); // a0 register
             halt_trap(s->pc, cpu.reg[10]);
             break;
 
@@ -23,14 +24,14 @@ void handle_syscall(Decode *s) {
                     }
                     cpu.reg[10] = count; // return value in a0
                 } else {
-                    Log("Syscall: write to unsupported fd %lu", fd);
+                    printf("Syscall: write to unsupported fd %lu\n", fd);
                     cpu.reg[10] = -1; // error
                 }
             }
             break;
 
         default:
-            Log("Unknown syscall: %lu", syscall_no);
+            printf("Unknown syscall: %lu\n", syscall_no);
             halt_trap(s->pc, -1);
             break;
     }

test/include/syscall.h

@@ -0,0 +1,30 @@
+#ifndef SYSCALL_H
+#define SYSCALL_H
+
+#include <stdint.h>
+
+#define SYSCALL_EXIT 93
+#define SYSCALL_WRITE 64
+
+static inline int64_t syscall(int64_t no, int64_t a0, int64_t a1, int64_t a2) {
+    register int64_t a7 asm("a7") = no;
+    register int64_t a0_ asm("a0") = a0;
+    register int64_t a1_ asm("a1") = a1;
+    register int64_t a2_ asm("a2") = a2;
+    asm volatile("ecall"
+                 : "+r"(a0_)
+                 : "r"(a7), "r"(a1_), "r"(a2_)
+                 : "memory");
+    return a0_;
+}
+
+static inline void exit(int64_t code) {
+    syscall(SYSCALL_EXIT, code, 0, 0);
+}
+
+static inline int64_t write(int64_t fd, const void *buf, int64_t count) {
+    return syscall(SYSCALL_WRITE, fd, (int64_t)buf, count);
+}
+
+
+#endif

test/src/exit.c

@@ -0,0 +1,5 @@
+#include <include/syscall.h>
+
+int main() {
+    exit(0);
+}