more userlaand stuff

kernel/syscall.c

@@ -0,0 +1,27 @@
+#include <stdint.h>
+
+#include "lib/print.h"
+
+typedef struct registers {
+    uint32_t gs, fs, es, ds;                           // Pushed manually
+    uint32_t edi, esi, ebp, esp, ebx, edx, ecx, eax;   // Pushed by pusha
+    uint32_t int_no, err_code;                         // Pushed manually
+    uint32_t eip, cs, eflags, useresp, ss;             // Pushed automatically by CPU
+} registers_t;
+
+int32_t sys_vga_text_write(char* buf);
+
+int32_t syscall(registers_t* regs) {
+    switch(regs->eax) {
+        case 1: {
+            return sys_vga_text_write((char*)regs->ebx);
+        }
+        default:
+            return -1;
+    }
+}
+
+int32_t sys_vga_text_write(char* buf) {
+    kprintf(buf);
+    return 0;
+}