Emit externals, jsr, eg that uses Kernal.

eg/hi.60pical

@@ -0,0 +1,9 @@
+external chrout 65490
+routine main {
+    lda #72
+    jsr chrout
+    lda #73
+    jsr chrout
+    lda #13
+    jsr chrout
+}

eg/sample.60pical

@@ -1,12 +0,0 @@
-reserve word score
-assign word screen 4000
-routine main {
-   lda screen
-   tax
-   tay
-   cmp score
-   ldx score
-   txa
-   ldy score
-   tya
-}

eg/simple.60pical

@@ -1,19 +0,0 @@
-assign word fnord 4000
-assign byte blerf 4002
-
-reserve byte foo
-reserve word bar
-
-routine hello {
-    lda fnord
-    cmp blerf
-    lda foo
-}
-
-routine bye {
-    lda fnord
-    cmp bar
-}
-
-routine byee {
-}

src/SixtyPical/Emitter.hs

@@ -24,6 +24,10 @@ emitDecl p (Assign name _ addr) = ".alias " ++ name ++ " " ++ (show addr)
 emitDecl p (Reserve name Byte) = name ++ ": .byte 0"
 emitDecl p (Reserve name Word) = name ++ ": .word 0"
 emitDecl p (Reserve name Vector) = name ++ ": .word 0"
+emitDecl p (External name addr) = ".alias " ++ name ++ " " ++ (show addr)
+emitDecl p d = error (
+    "Internal error: sixtypical doesn't know how to " ++
+    "emit assembler code for '" ++ (show d) ++ "'")
 
 emitRoutines _ [] = ""
 emitRoutines p (rout:routs) =
@@ -124,6 +128,9 @@ emitInstr p r (COPYROUTINE src (NamedLocation dst)) =
 emitInstr p r (JMPVECTOR (NamedLocation dst)) =
     "jmp (" ++ dst ++ ")"
 
+emitInstr p r (JSR routineName) =
+    "jsr " ++ routineName
+
 emitInstr p r i = error (
     "Internal error: sixtypical doesn't know how to " ++
     "emit assembler code for '" ++ (show i) ++ "'")