From b34ff2bdec05da58f1b7fa38ccb7f9d2dc34fd2d Mon Sep 17 00:00:00 2001
From: David Given <dg@cowlark.com>
Date: Sun, 10 Feb 2019 18:44:47 +0100
Subject: [PATCH] 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 | 40 +++++++++++++++++++++++++++++++++-------
 1 file changed, 33 insertions(+), 7 deletions(-)

diff --git a/mach/i80/ncg/table b/mach/i80/ncg/table
index 046c99963..b0fcf3a6a 100644
--- a/mach/i80/ncg/table
+++ b/mach/i80/ncg/table
@@ -702,14 +702,33 @@ pat ngi $1==4
 kills ALL
 gen Call {label,".ngi4"}
 
-pat loc sli ($1 == 8) && ($2 == 2)
-with hl_or_de
-gen move %1.2, %1.1
-    mvi %1.2, {const1,0}        yields %1
+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
+         mov %1.1, %1.2
+         mvi %1.2, {const1, 0}
+      yields %1
 
 pat sli $1==2
-kills ALL
-gen Call {label,".sli2"}		yields de
+   kills ALL
+      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