From abba68c94194355769280512a6080d6c58b65b90 Mon Sep 17 00:00:00 2001
From: Luke Kenneth Casson Leighton <lkcl@lkcl.net>
Date: Sat, 28 Mar 2020 19:41:12 +0000
Subject: [PATCH] add fixed trap

---
 openpower/isa/fixedtrap.mdwn | 55 ++++++++++++++++++++++++++++++++++++
 1 file changed, 55 insertions(+)
 create mode 100644 openpower/isa/fixedtrap.mdwn

diff --git a/openpower/isa/fixedtrap.mdwn b/openpower/isa/fixedtrap.mdwn
new file mode 100644
index 000000000..ea94cfaa1
--- /dev/null
+++ b/openpower/isa/fixedtrap.mdwn
@@ -0,0 +1,55 @@
+# Trap Word Immediate
+
+twi TO,RA,SI
+
+    a <- EXTS((RA)[32:63])
+    if (a < EXTS(SI)) & TO[0]  then TRAP
+    if (a > EXTS(SI)) & TO[1]  then TRAP
+    if (a = EXTS(SI)) & TO[2]  then TRAP
+    if (a <u EXTS(SI)) & TO 3 then TRAP
+    if (a >u EXTS(SI)) & TO 4 then TRAP
+
+# Trap Word 
+
+tw TO,RA,RB
+
+    a <- EXTS((RA)[32:63])
+    b <- EXTS((RB)[32:63])
+    if (a < b) & TO[0] then TRAP
+    if (a > b) & TO[1] then TRAP
+    if (a = b) & TO[2] then TRAP
+    if (a <u b) & TO[3] then TRAP
+    if (a >u b) & TO[4] then TRAP
+
+# Trap Doubleword Immediate 
+
+tdi TO,RA,SI
+
+    a <- (RA)
+    b <- EXTS(SI)
+    if (a < b) & TO[0] then TRAP
+    if (a > b) & TO[1] then TRAP
+    if (a = b) & TO[2] then TRAP
+    if (a <u  b) & TO[3] then TRAP
+    if (a >u  b) & TO[4]  then TRAP
+
+# Trap Doubleword 
+
+td TO,RA,RB
+
+    a <- (RA)
+    b <- (RB)
+    if (a < b) & TO[0] then TRAP
+    if (a > b) & TO[1] then TRAP
+    if (a = b) & TO[2] then TRAP
+    if (a <u b) & TO[3] then TRAP
+    if (a >u b) & TO[4]  then TRAP
+
+# Integer Select
+
+isel RT,RA,RB,BC
+
+    if RA=0 then a <-0 else a <-  (RA)
+    if CR[BC+32]=1 then RT <- a
+    else           RT <- (RB)
+
-- 
2.30.2