From c60dfb47fc448fc2da19bf9e295554ef65a65ce9 Mon Sep 17 00:00:00 2001
From: julianb0 <spectral@os-k.eu>
Date: Wed, 10 Jul 2019 20:11:35 +0200
Subject: [PATCH] command.com

---
 ka/doskrnl.k         |  1 -
 ka/sys/fileapi.k     |  0
 ka/sys/intr/common.k | 13 ++++---
 ka/sys/intr/trap0.k  |  6 ++--
 ka/usr/cmd/main.k    | 86 ++++++++++++++++++++++++++++++++++++++++++--
 vm/in/STRING         |  8 ++---
 6 files changed, 97 insertions(+), 17 deletions(-)
 delete mode 100644 ka/sys/fileapi.k

diff --git a/ka/doskrnl.k b/ka/doskrnl.k
index 4067430..b07f897 100644
--- a/ka/doskrnl.k
+++ b/ka/doskrnl.k
@@ -44,6 +44,5 @@ include "sys/drv/diskdev.k"
 include "sys/intr/common.k"
 include "sys/intr/trap0.k"
 
-include "sys/tests.k"
 include "sys/main.k"
 
diff --git a/ka/sys/fileapi.k b/ka/sys/fileapi.k
deleted file mode 100644
index e69de29..0000000
diff --git a/ka/sys/intr/common.k b/ka/sys/intr/common.k
index 93d5773..130b461 100644
--- a/ka/sys/intr/common.k
+++ b/ka/sys/intr/common.k
@@ -6,17 +6,19 @@ TrapHandlers.prolog:
     mov q[rbp-16], r12
     mov q[rbp-24], r13
     sub rsp, rbp, 24
-    xor rdx, rdx
+
+    mov rdx, cr2
 
     ; nx0 = caller's cr2
-    push cr2
     mov ax0, r12
     mov ax1, $cr2
     iocall CPUDEV, RFS.LoadReg.slot
-    mov nx0, cr2
-    pop cr2
 
-    jmp rcx ; go back
+    mov nx0, cr2
+    mov cr2, rdx
+    xor rdx, rdx
+
+    jmp rcx
 
 TrapHandlers.epilog:
     mov r13, q[rbp-24]
@@ -36,5 +38,6 @@ TrapHandlers.epilog:
 
     mov ax0, r11
     call IDT.DoneHandling
+
     iret
 
diff --git a/ka/sys/intr/trap0.k b/ka/sys/intr/trap0.k
index 9d36cb6..bab4589 100644
--- a/ka/sys/intr/trap0.k
+++ b/ka/sys/intr/trap0.k
@@ -22,9 +22,9 @@ trap0_handler:
 .fini:
     jmp TrapHandlers.epilog
 
-;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
-;;; Syscall implementations ;;;
-;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;------------------------------------------------;
+;             Syscall implementations            ;
+;------------------------------------------------;
 
 ;
 ; Pass control to COMMAND.COM in frame 0
diff --git a/ka/usr/cmd/main.k b/ka/usr/cmd/main.k
index 6a0e2b9..010985b 100644
--- a/ka/usr/cmd/main.k
+++ b/ka/usr/cmd/main.k
@@ -1,8 +1,90 @@
 ; The OS/K Team licenses this file to you under the MIT license.
 ; See the LICENSE file in the project root for more information.
 
+argbuf.size := 256
+argbuf = [argbuf.size]
+argv0 = [argbuf.size]
+argv1pos = 0
+
+stdin_echoing = 1
+
+ps1 = "C:\\> "
+
 main:
+
+.print_prompt:
+    mov rcx, STRLEN_MAX
+    mov rdx, ps1
+    prns.rep.nz rdx
+
+    ; empty argbuf
+    mov rcx, argbuf.size
+    mov rdx, argbuf
+    stosb.rep rdx, 0
+
+    ; iterator through argbuf
+    xor rcx, rcx
+
+.input_loop:
+    pause
+    pause
+
+    ; Fill .buf with user input
+    scan rax
+    b.z rax, 0, .input_loop
+
+    cmp b[stdin_echoing], 1
+    prn.z rax
+    b.z rax, 10, .extract_argv0
+
+    ; when max line length is reached,
+    ; force a newline
+    b.z rcx, argbuf.size, .extract_argv0
+
+    ; add character to buffer and increase iterator (rcx)
+    add rdx, rcx, argbuf
+    mov b[rdx], rax
+    inc rcx
+
+    ; another one
+    jmp .input_loop
+
+.extract_argv0:
+
+    ; find first whitespace or null-terminator
+    mov rcx, argbuf.size
+    mov rdx, argbuf
+    scasb.rep.nz rdx, ' '
+
+    ; argv1 exists? if so, save its position
+    ; (to do)
+
+    ; extract argv0
+    sub rcx, argbuf.size, rcx
+    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
+    b.z rax, 0, .handle_DIR
+
+    ; fallthrough
+
+.exec_prog:
+    jmp .print_prompt
+
+;
+; call builtins
+;
+.handle_DIR:
     call builtins.dir
-
-    ret
+    jmp .print_prompt
 
diff --git a/vm/in/STRING b/vm/in/STRING
index f05ae66..4dd3f08 100644
--- a/vm/in/STRING
+++ b/vm/in/STRING
@@ -15,10 +15,6 @@
 #           %str = %str - sizeof(x)
 #       FI
 #
-# When no parameters are given, %str = RDI and $val = RAX
-# When one parameter is given, %str = RDI and $val = $1
-# When two parameters are given, %str = $1 and $val = $2
-#
 stosb r ri
 stosw r ri
 stosl r ri
@@ -97,7 +93,7 @@ cmpsq r r
 # Behaves precisely like CMPSx, except in the following case:
 #   - If both [%1] and [%2] are zero, clears ZF (indicating NOT EQUAL)
 #
-# This prevents 'CMPZSx.REP.Z' from looping infinitely when both strings
+# This prevents 'CMPZSx.REP.Z' from ignoring null-terminators when both strings
 # have the exact same content; this allows for short strcmp's
 #
 cmpzsb r r
@@ -108,7 +104,7 @@ cmpzsq r r
 #
 # Move value from string to string (MOVSx)
 #
-#       [%1] = [%1]
+#       [%1] = [%2]
 #       IF (DF == 0) THEN
 #           %1 = %1 + sizeof(x)
 #           %2 = %2 + sizeof(x)