From: lkcl <lkcl@web>
Date: Sun, 15 May 2022 23:49:29 +0000 (+0100)
Subject: (no commit message)
X-Git-Tag: opf_rfc_ls005_v1~2209
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=b1c036f5125e2944e355c399e375b1faaa61b9dd;p=libreriscv.git

---

diff --git a/openpower/sv/bitmanip.mdwn b/openpower/sv/bitmanip.mdwn
index f7f4a37bd..32f6c2dca 100644
--- a/openpower/sv/bitmanip.mdwn
+++ b/openpower/sv/bitmanip.mdwn
@@ -96,7 +96,8 @@ TODO: convert all instructions to use RT and not RS
 | -- | -- | --- | ---  | -----   | --------  |--| ------   | -------- |
 | NN | RT | RA  |itype/| im0-4   | im5-7  00 |0 | xpermi  |           |
 | NN | RT | RA  | RB   | RC      | nh 00  00 |1 | binlut |           |
-| NN |    |     |      |         | -  01  00 |1 | rsvd    |           |
+| NN | RT | RA  | RB   | BFC//   | 0  01  00 |1 | bincrlut    |           |
+| NN |    |     |      |         | 1  01  00 |1 | rsvd    |           |
 | NN |    |     |      |         | -  10  00 |1 | rsvd    |           |
 | NN |    |     |      |         | 0  11  00 |1 | svshape    |           |
 | NN |    |     |      |         | 1  11  00 |1 | svstep   |           |
@@ -185,9 +186,12 @@ Binary lookup is a dynamic LUT2 version of ternlogi. Firstly, the
 lookup table is 4 bits wide not 8 bits, and secondly the lookup
 table comes from a register not an immediate.
 
-| 0.5|6.10|11.15|16.20| 21..25|26..30|31|
-| -- | -- | --- | --- | ----- | ---- |--|
-| NN | RT | RA  | RB  | RC    |00011 |nh|
+| 0.5|6.10|11.15|16.20| 21..25|26..30 |31|
+| -- | -- | --- | --- | ----- |------ |--|
+| NN | RT | RA  | RB  | RC    |nh 0000|1 |
+| NN | RT | RA  | RB  | BFA// |0  0100|1 |
+
+For binlut:
 
     lut2(imm, a, b):
         idx = b << 1 | a
@@ -197,6 +201,11 @@ table comes from a register not an immediate.
     for i in range(64): 
         RT[i] = lut2(imm, RB[i], RA[i]) 
 
+For bincrlut, `BFA` selects the 4-bit CR Field as the LUT2:
+
+    for i in range(64): 
+        RT[i] = lut2(CR{BFA}, RB[i], RA[i]) 
+
 *Programmer's note: a dynamic ternary lookup may be synthesised from
 a pair of `binlut` instructions followed by a `ternlogi` to select which
 to merge. Use `nh` to select which nibble to use as the lookup table