sys_read/open/close

user/pedicel.S

@@ -1,7 +1,8 @@
 bits 64
 
 section .data
-hello db 0x0A, 0x0D, "User program 2 speaking", 0x0A, 0x0D, 0
+hello db 0x0A, 0x0D, "TEST PROGRAM...", 0x0A, 0x0D, 0
+filename db "wow.txt", 0
 
 section .text
 
@@ -9,7 +10,29 @@ _start:
     mov rax, 0x1    ;sys_write
     mov rdi, 0x1    ;stdout
     lea rsi, [rel hello]
-    mov rdx, 27     ;count
+    mov rdx, 19     ;count
+    int 0x80
+
+    ; Open a file
+    mov rax, 0x2            ;sys_open
+    lea rdi, [rel filename] ;filename
+    mov rsi, 0x0            ;flags
+    int 0x80
+
+    mov rdi, rax            ;fd
+    mov rax, 0x0            ;sys_read
+    lea rsi, [rel buf]      ;buf
+    mov rdx, 33             ;count
+    int 0x80
+
+    mov rax, 0x1        ;sys_write
+    mov rdi, 0x1        ;stdout
+    lea rsi, [rel buf]  ;buf
+    mov rdx, 33         ;count
+    int 0x80
+
+    mov rax, 0x3        ;sys_close
+    mov rdi, 0x3        ;fd
     int 0x80
 
 ; when we are ready to have an os specific toolchain,
@@ -22,4 +45,7 @@ _start:
     int 0x80
 
 .loop:
-    jmp .loop
+    jmp .loop
+
+section .bss
+buf resb 10

user/wow.txt

@@ -0,0 +1 @@
+hi from a file opened in usermode