From: Jacob Lifshay <programmerjake@gmail.com>
Date: Thu, 20 Apr 2023 00:45:44 +0000 (-0700)
Subject: merge integer min/max instructions and correct section ordering
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=919776f50ae62b791e61c689ca487f82eabc4f82;p=libreriscv.git

merge integer min/max instructions and correct section ordering
---

diff --git a/openpower/sv/rfc/ls013.mdwn b/openpower/sv/rfc/ls013.mdwn
index d7c91064b..8145cd18c 100644
--- a/openpower/sv/rfc/ls013.mdwn
+++ b/openpower/sv/rfc/ls013.mdwn
@@ -220,116 +220,44 @@ semantics therefore Saturated variants of these instructions need not be propose
 | 101   | `maxuw RT,RA,RB` | `RT = (uint32_t)RA > (uint32_t)RB ? RA : RB` |
 | 110   | `minsw RT,RA,RB` | `RT =  (int32_t)RA < (int32_t)RB  ? RA : RB` |
 | 111   | `maxsw RT,RA,RB` | `RT =  (int32_t)RA > (int32_t)RB  ? RA : RB` |
-       
-## Minimum Unsigned
 
-X-Form
+## Integer Min/Max MM-Form
 
-```
-    |0   |6   |11  |16   |21  |31  |
-    | PO | RT | RA | RB  | XO | Rc |
-```
-
-* minu RT, RA, RB
-* minu. RT, RA, RB
-
-
-```
-    if (RA) <u (RB) then
-        RT <- (RA)
-    else
-        RT <- (RB)
-```
-
-Special Registers altered:
-
-```
-    CR0     (if Rc=1)
-```
-
-Compute the unsigned minimum of RA and RB and store the result in RT.
-
-## Maximum Unsigned
-
-X-Form
-
-```
-    maxu RT, RA, RB
-    maxu. RT, RA, RB
-```
-
-```
-    |0   |6   |11  |16   |21  |31  |
-    | PO | RT | RA | RB  | XO | Rc |
-```
-
-```
-    if (RA) >u (RB) then
-        RT <- (RA)
-    else
-        RT <- (RB)
-```
-
-Special Registers altered:
-
-```
-    CR0     (if Rc=1)
-```
-
-Compute the unsigned maximum of RA and RB and store the result in RT.
-
-\newpage{}
-
-## Minimum
-
-X-Form
-
-```
-    min RT, RA, RB
-    min. RT, RA, RB
-```
-
-```
-    |0   |6   |11  |16   |21  |31  |
-    | PO | RT | RA | RB  | XO | Rc |
-```
-
-```
-    if (RA) < (RB) then
-        RT <- (RA)
-    else
-        RT <- (RB)
-```
-
-Special Registers altered:
-
-```
-    CR0     (if Rc=1)
-```
-Compute the signed minimum of RA and RB and store the result in RT.
-
-## Maximum
-
-X-Form
-
-```
-    max RT, RA, RB
-    max. RT, RA, RB
-```
+* minmax RT, RA, RB, MMM
+* minmax. RT, RA, RB, MMM
 
 ```
-    |0   |6   |11  |16   |21  |31  |
-    | PO | RT | RA | RB  | XO | Rc |
+    |0    |6    |11   |16   |21   |24 |25  |31  |
+    | PO  | RT  | RA  | RB  | MMM | / | XO | Rc |
 ```
 
 ```
-    if (RA) > (RB) then
+    a <- (RA)
+    b <- (RB)
+    if MMM[0] then  # word mode
+        # shift left by XLEN/2 to make the dword comparison
+        # do word comparison of the original inputs
+        a <- a[XLEN/2:XLEN-1] || [0] * XLEN/2
+        b <- b[XLEN/2:XLEN-1] || [0] * XLEN/2
+    if MMM[1] then  # signed mode
+        # invert sign bits to make the unsigned comparison
+        # do signed comparison of the original inputs
+        a[0] <- !a[0]  # convert
+        b[0] <- !b[0]
+    if MMM[2] then  # max mode
+        # swap a and b to make the less than comparison do
+        # greater than comparison of the original inputs
+        t <- a
+        a <- b
+        b <- t
+    if a <u b then
         RT <- (RA)
     else
         RT <- (RB)
 ```
 
-Compute the signed maximum of RA and RB and store the result in RT.
+Compute the integer minimum/maximum according to `MMM` of `RA` and `RB` and
+store the result in `RT`.
 
 Special Registers altered: