add bcd

diff --git a/openpower/isa/bcd.mdwn b/openpower/isa/bcd.mdwn
new file mode 100644 (file)
index 0000000..ff1afc5
--- /dev/null
+++ b/openpower/isa/bcd.mdwn
@@ -0,0 +1,28 @@
+# Convert Declets To Binary Coded Decimal  
+
+cdtbcd RA, RS
+
+    do i = 0 to 1
+      n <- i * 32
+      RA[n+0:n+7] <- 0 
+      RA[n+8:n+19 ] <- DPD_TO_BCD( (RS)[n+12:n+21] ) 
+      RA[n+20:n+31] <- DPD_TO_BCD( (RS)[n+22:n+31] )
+
+# Add and Generate Sixes
+
+addg6s RT,RA,RB
+
+    do i = 0 to 15
+        dci <- carry_out(RA[4xi:63] + RB[4xi:63])
+        c <- [dc[0]]*4 || [dc[1]]*4 || ... || [dc[15]]*4
+        RT <- (¬c) & 0x6666_6666_6666_6666
+
+# Convert Binary Coded Decimal To Declets  
+
+cbcdtd RA, RS
+
+    do i = 0 to 1
+      n <- i * 32
+      RA[n+0:n+11] <- 0 
+      RA[n+12:n+21] <- BCD_TO_DPD( (RS)[n+8:n+19] ) 
+      RA[n+22:n+31] <- BCD_TO_DPD( (RS)[n+20:n+31] )