cmd

ka/command.k

@@ -11,6 +11,7 @@ start:
     xor rbp, rbp
     
     cls
+    cld
     call main
 
     mov rax, Sys.HLT

ka/crt/str/strcmp.k

@@ -6,8 +6,8 @@
 ;
 ; Returns:
 ;    0 if the contents of both strings are equal
-;    1 if the first character that does not match has a greater value in str1 than in str2
+;   >0 if the first character that does not match has a greater value in str1 than in str2
-;   -1 if the first character that does not match has a lower value in str1 than in str2
+;   <0 if the first character that does not match has a lower value in str1 than in str2
 ;
 strcmp:
     mov ax2, STRLEN_MAX
@@ -21,11 +21,10 @@ strncmp:
     mov.cxz rax, 0
     ret.cxz
 
-    cmpzsb.rep.e ax0, ax1
+    cmpzsb.rep.z ax0, ax1
 
-    mov rax, b[ax0]
+    mov rax, b[ax0-1]
-    sub rax, b[ax1]
+    sub rax, b[ax1-1]
-    sgn rax, rax
 
     ret
 

ka/usr/cmd/main.k

@@ -33,6 +33,24 @@ main:
     scan rax
     b.z rax, 0, .input_loop
 
+    ; backspace character?
+    b.nz rax, 8, .handle_input
+
+    ; anything to delete?
+    b.z rcx, 0, .input_loop
+
+    ; delete it
+    dec rcx
+    add rdx, rcx, argbuf
+    mov b[rdx], 0
+
+    ; update screen
+    cmp b[stdin_echoing], 1
+    prn.z 8
+
+    jmp .input_loop
+
+.handle_input:
     cmp b[stdin_echoing], 1
     prn.z rax
     b.z rax, 10, .extract_argv0
@@ -51,6 +69,10 @@ main:
 
 .extract_argv0:
 
+    ; did we read anything at all?
+    ; if not, just go back to waiting input
+    b.z rcx, 0, .print_prompt
+
     ; find first whitespace or null-terminator
     mov rcx, argbuf.size
     mov rdx, argbuf
@@ -59,18 +81,21 @@ main:
     ; argv1 exists? if so, save its position
     ; (to do)
 
+    ; empty argv0
+    mov rcx, argbuf.size
+    mov rax, argv0
+    stosb.rep rax, 0
+
     ; extract argv0
-    sub rcx, argbuf.size, rcx
+    sub rcx, rdx, argbuf
     mov rdx, argbuf
     mov rax, argv0
     movsb.rep rax, rdx
 
-    ; null-terminate argv0
-    mov b[rax], 0
-
 .detect_builtin:
 
 .builtin_dir = "dir"
+
     mov ax0, argv0
     mov ax1, .builtin_dir
     call strcmp
@@ -79,8 +104,21 @@ main:
     ; fallthrough
 
 .exec_prog:
+
+    ; fallthrough
+
+.not_found:
+    mov rcx, STRLEN_MAX
+    mov rdx, argv0
+    prns.rep.nz rdx
+
+    mov rdx, .errmsg
+    prns.rep.nz rdx
+
     jmp .print_prompt
 
+.errmsg = " : command not found\n"
+
 ;
 ; call builtins
 ;