From a91ab5c59995342cbe4a1d7d400ebea6660290f0 Mon Sep 17 00:00:00 2001
From: David Given <dg@cowlark.com>
Date: Fri, 8 Feb 2019 21:35:14 +0100
Subject: [PATCH] Somehow the implementation of rst 2 got lost, with hilarious
 results. Also fix some register corruption issues (I hope).

---
 mach/i80/libem/rst.s | 22 ++++++++++++++++++++++
 mach/i80/ncg/table   |  7 +++----
 2 files changed, 25 insertions(+), 4 deletions(-)

diff --git a/mach/i80/libem/rst.s b/mach/i80/libem/rst.s
index 37025ef17..c0d5984d8 100644
--- a/mach/i80/libem/rst.s
+++ b/mach/i80/libem/rst.s
@@ -9,8 +9,11 @@
 .rst_init:
     mvi a, 0xc3     ! jmp <a16>
     sta 0x08
+    sta 0x10
     lxi h, rst1
     shld 0x09
+    lxi h, rst2
+    shld 0x11
     ret
 
     ! de = [bc+const1] (remember bc is the frame pointer)
@@ -30,3 +33,22 @@ rst1:
     inx h
     mov d, m
     ret
+
+    ! [bc+const1] = de (remember bc is the frame pointer)
+rst2:
+    pop h
+    mov a, m
+    inx h
+    push h
+
+	mov l, a
+	ral
+	sbb a
+	mov h, a
+
+	dad b
+    mov m, e
+    inx h
+    mov m, d
+    ret
+
diff --git a/mach/i80/ncg/table b/mach/i80/ncg/table
index ab99b882e..0e3864a44 100644
--- a/mach/i80/ncg/table
+++ b/mach/i80/ncg/table
@@ -245,8 +245,7 @@ pat ldc					yields {const2,highw($1)}
 
 #ifdef USE_I80_RSTS
    pat lol sfit($1, 8)
-      kills hlreg
-      uses hlreg, dereg
+      uses hlreg, areg, dereg
       gen
          rst {const1, 1}
          data1 {const1, $1}
@@ -462,8 +461,8 @@ with dereg				yields de de leaving stl $1
 
 #ifdef USE_I80_RSTS
    pat stl sfit($1, 8)
-	  with dereg
-      kills hlreg, areg
+	   with dereg
+      uses hlreg, areg
       gen
          rst {const1, 2}
          data1 {const1, $1}