dos

dos/main.k

@@ -9,21 +9,20 @@ main:
 
     mov ax0, .msg
     call print
-    break
 
     mov ax0, .buf
     mov ax1, .msg
     call strrev
-    break
 
+    prn 10
     mov ax0, .buf
     call print
 
     leave
     ret
 
-.msg = "Hello World :)\n"
-.buf = "               "
+.msg = "Hello World :)"
+.buf = "!!!!!!!!!!!!!!!!"
 
 ;
 ; Exit function

dos/str/strrev.k

@@ -10,8 +10,11 @@ strrev:
     jz .4
 
     ; save str's location
-    mov rdx, ax1
+    ; xxx why is dec'ing needed?
+    lea rdx, b[ax1 + -1]
 
+    ; go to str's end, just before
+    ; the null terminator
 .1:
     test b[ax1+1], b[ax1+1]
     jz .2
@@ -19,6 +22,8 @@ strrev:
     inc ax1
     jmp .1
 
+    ; copy, going backward though str
+    ; and forward through buf 
 .2:
     mov b[ax0], b[ax1]
 

pc/mem.c

@@ -94,6 +94,15 @@ void writemem8(ctx_t *ctx, ulong val, ulong addr)
 
     ushort v = ctx->mp[real];
 
+    if (!(addr % 2)) {
+        ctx->mp[real] = ((v & 0xFF00) << 8) | (val & 0xFF);
+    }
+
+    else {
+        ctx->mp[real] = (v & 0xFF) | (((val & 0xFF) << 8));
+    }
+
+/*
     if (addr % 2) {
         ctx->mp[real] = (v & 0xFF00) | (val & 0xFF);
     }
@@ -101,6 +110,7 @@ void writemem8(ctx_t *ctx, ulong val, ulong addr)
     else {
         ctx->mp[real] = (v & 0xFF) | (((val & 0xFF) << 8));
     }
+*/
 }
 
 void writemem16(ctx_t *ctx, ulong val, ulong addr)