implement our own readdir and strtol, syscall builtin

src/codegen_x86_64.rs

@@ -106,7 +106,7 @@ section .text
         );
 
         // take that rustfmt
-        for name in "syscall,malloc,realloc,free,snprintf,strtol,system,opendir,readdir,closedir,gettimeofday,send,write,read,close,getchar,gethostbyname".split(",")
+        for name in "malloc,realloc,free,snprintf,system,gettimeofday,send,write,read,close,getchar,gethostbyname".split(",")
         {
             emit!(&mut self.output, "extern {}", name);
             emit!(&mut self.output, "c.{} equ {}", name, name);
@@ -121,6 +121,12 @@ _builtin_read8:
     mov al, byte [rdi]
     ret
 
+section .text._builtin_read16
+_builtin_read16:
+    xor rax, rax
+    mov ax, word [rdi]
+    ret
+
 section .text._builtin_read32
 _builtin_read32:
     mov eax, dword [rdi]
@@ -140,6 +146,18 @@ section .text._builtin_set64
 _builtin_set64:
     mov [rdi], rsi
     ret
+
+section .text._builtin_syscall
+_builtin_syscall:
+    mov rax, rdi
+    mov rdi, rsi
+    mov rsi, rdx
+    mov rdx, rcx
+    mov r10, r8
+    mov r8,  r9
+    mov r9,  [rsp+8]
+    syscall
+    ret
 "
         );
         Ok(())