number reading routine

in.asm

@@ -1,7 +1,33 @@
+:> end
    cs push \ copy code segment to data segment
    ds pop
 
-   ax 0 # mov
+\ read number
+\ clobbers: ax, bx, cx, dx
+   dx dx xor
+   cx cx xor
+   bx 10 # mov
+   dx push
+:> readnext
+   ax &h0100 # mov
+   &h21 int
+
+   :> readover  
+   al in@ 0 # cmp
+   readover jl
+   al in@ 9 # cmp
+   readover jg
+   cl al mov
+   cl in@ 0 # sub
+   ax pop
+   bx mul
+   ax cx add
+   ax push
+   readnext jmps
+readover <:
+   ax pop
+
+   \ ax 0 # mov
 \ print number
 \ in: ax = number
 \ clobbers: ax, bx, cx, dx
@@ -18,7 +44,7 @@
 
 :> moredigits
    dx pop
-   dl 48 # add
+   dl in@ 0 # add
    ax &h0200 # mov
    &h21 int
    bx dec
@@ -26,4 +52,4 @@
 
    0 .EXIT
 
-   cx 11 # mov
+end <: