polmon: refactor jump & stdlib

stdlib.c

@@ -0,0 +1,31 @@
+int getchar() {
+    register char c asm ("al");
+    asm volatile (
+            "movb $0x00, %%ah\n\t"
+            "int $0x16"
+            : "=r" (c)
+            :: "ah", "cc"
+            );
+    return c;
+}
+
+int putchar(int c) {
+    asm volatile (
+            "push %%bp          \n\t"
+            "mov %0, %%ax      \n\t"
+            "movb $0x0e, %%ah   \n\t"
+            "movb $0, %%bh      \n\t"
+            "int $0x10          \n\t"
+            "pop %%bp           \n\t"
+            :: "r" (c)
+            : "ax", "bh", "cc"
+            );
+    return 0;
+}
+
+int puts(const char* s) {
+    while (*s) {
+        putchar(*s++);
+    }
+    return 0;
+}