Teach the i80 code generator how to do left shifts by using dad hl; prevents it

from calling out to .sli2 for simple shifts. Shrinks Star Trek from 40055 bytes
to 39976.

mach/i80/ncg/table

@@ -702,14 +702,33 @@ pat ngi $1==4
 kills ALL
 gen Call {label,".ngi4"}
 
+pat loc sli ($1==1) && ($2==2)
+   with hlreg
+      gen
+         dad hl
+      yields hl
+   
+pat loc sli ($1>=2) && ($1<=7) && ($2==2)
+   with hlreg
+      gen
+         dad hl
+      yields hl
+      leaving
+         loc $1-1
+         sli 2
+   
 pat loc sli ($1==8) && ($2==2)
    with hl_or_de
-gen move %1.2, %1.1
-    mvi %1.2, {const1,0}        yields %1
+      gen
+         mov %1.1, %1.2
+         mvi %1.2, {const1, 0}
+      yields %1
 
 pat sli $1==2
    kills ALL
-gen Call {label,".sli2"}		yields de
+      gen
+         Call {label,".sli2"}
+	yields de
 
 pat sli $1==4
 kills ALL
@@ -761,7 +780,14 @@ kills ALL
 gen mvi a,{const1,0}
     Call {label,".dvi4"}
 
-pat slu						leaving sli $1
+pat loc slu ($2==2)
+   leaving
+      loc $1
+      sli $2
+   
+pat slu
+   leaving
+      sli $1
 
 pat loc sru ($1 == 8) && ($2 == 2)
 with hl_or_de