Stacker crate didn't do anything after all; fixed a couple bugs Will found, implemented shift / enter / backspace

vemu/src/typewriter.asm

@@ -2,6 +2,11 @@
 screen: .equ 0x10000
 reg: .equ 16
 
+lshift: .equ 0xe1
+rshift: .equ 0xe5
+enter: .equ 0x28
+backspace: .equ 0x2a
+
 ;;;;; Start
     push on_key
     setiv 5
@@ -66,24 +71,71 @@ on_key:
     setint 1 ; this can be reentrant, doesn't hurt anything
     call is_press ; check for press
     #if
-        call is_alpha
-        brnz @putc
-        call is_punc
+        call is_ret
+        brnz @newline
+        call is_back
+        brnz @handle_backspace
+        call is_printable
         brnz @putc
+        call is_shift
+        brnz @set_shift
+    ;   if backspace, clear cursor and dec
         pop
         ret
     #else
-    ; TODO:
-    ;   if is punc, look up in punc map and print
-    ;   if shift, set shift flag
-    ;   if return inc cursor
-    ;   if backspace, clear cursor and dec
-    ; else release:
-    ;   if shift, clear shift flag
+        call is_shift
+        brnz @clear_shift
+        pop
+        ret
+    #end
+    ret
+
+newline:
+    loadw cursor
+    sub screen
+    add 40
+    dup
+    gt 40 * 30 - 1
+    #if
+    pop
+    push 40
+    #else
+    dup
+    mod 40
+    sub
+    #end
+    add screen
+    storew cursor
+    ret
+
+handle_backspace:
+    loadw cursor
+    sub screen
+    dup
+    mod 40
+    #if
+    sub 1
+    add screen
+    dup
+    swap 32 ; a space
+    store
+    storew cursor
+    #else
     pop
     #end
     ret
 
+
+set_shift:
+    push shift_table
+    storew current_table
+    ret
+
+clear_shift:
+    push default_table
+    storew current_table
+    ret
+
 is_press: ; ( event -- key bool )
     dup
     and 0xff
@@ -91,39 +143,47 @@ is_press: ; ( event -- key bool )
     and 0xff00
     ret
 
-is_ret: ; ( key -- 1 ) or ( key -- key 0 )
+is_ret:
+    push enter
+    jmp is_key
+
+is_back:
+    push backspace
+    jmp is_key
+
+is_shift: ; ( key -- 1 ) or ( key -- key 0 )
+    push lshift
+    call is_key
+    brz @+2
+    ret 1
+    push rshift
+    jmp is_key
+
+is_key: ; ( key1 key2 -- 1 ) or ( key1 key2 -- key1 0 )
+    swap
     dup
-    sub 0x28
-    brnz @+3
+    pushr
+    sub
+    #unless ; they're equal
+    popr
     pop
     ret 1
+    #else ; they're not
+    popr
     ret 0
+    #end
 
-is_alpha: ; ( key -- ch 1 ) or ( key -- key 0 )
+is_printable: ; ( key -- ch 1 ) or ( key -- key 0 )
     dup
     dup
     gt 0x03
     swap
-    lt 0x28
-    and
-    #if
-    sub 0x04
-    add alpha_table
-    load
-    ret 1
-    #end
-    ret 0
-
-is_punc: ; ( key -- ch 1 ) or (key -- key 0 )
-    dup
-    dup
-    gt 0x2b
-    swap
     lt 0x39
     and
     #if
-    sub 0x2c
-    add punc_table
+    sub 0x04
+    loadw current_table
+    add
     load
     ret 1
     #end
@@ -139,7 +199,9 @@ putc: ; ( ch -- ) (also modifies cursor)
     storew cursor
     ret
 
+default_table: .db "abcdefghijklmnopqrstuvwxyz1234567890???? -=[]\\?;'`,./"
+shift_table: .db "ABCDEFGHIJKLMNOPQRSTUVWXYZ!@#$%^&*()???? _+{}|?:\"~<>?"
+
 cursor: .db screen + 40
 msg: .db "Type something:\0"
-alpha_table: .db "abcdefghijklmnopqrstuvwxyz1234567890"
-punc_table: .db " -=[]\\?;'`,./"
+current_table: .db default_table