From: Luke Kenneth Casson Leighton <lkcl@lkcl.net>
Date: Mon, 20 Mar 2023 13:19:14 +0000 (+0000)
Subject: add wording section to crternlogi ls007
X-Git-Tag: opf_rfc_ls001_v3~136
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=b486fb63e198031e89a6e6e674e82fde15385fd6;p=libreriscv.git

add wording section to crternlogi ls007
https://bugs.libre-soc.org/show_bug.cgi?id=1017
---

diff --git a/openpower/sv/rfc/ls007.mdwn b/openpower/sv/rfc/ls007.mdwn
index ca816986e..ea08f6faa 100644
--- a/openpower/sv/rfc/ls007.mdwn
+++ b/openpower/sv/rfc/ls007.mdwn
@@ -163,10 +163,10 @@ XO (26:30)
 
 # Ternary Logic Immediate
 
-TLI-form
-
 Add this section to Book I 3.3.13
 
+TLI-form
+
 * `ternlogi RT, RA, RB, TLI` (`Rc=0`)
 * `ternlogi. RT, RA, RB, TLI` (`Rc=1`)
 
@@ -177,18 +177,18 @@ Add this section to Book I 3.3.13
 Pseudocode:
 
 ```
-result <- (~RT&~RA&~RB & TLI[0]*XLEN |
-          (~RT&~RA& RB & TLI[1]*XLEN |
-          (~RT& RA&~RB & TLI[2]*XLEN |
-          (~RT& RA& RB & TLI[3]*XLEN |
-          ( RT&~RA&~RB & TLI[4]*XLEN |
-          ( RT&~RA& RB & TLI[5]*XLEN |
-          ( RT& RA&~RB & TLI[6]*XLEN |
-          ( RT& RA& RB & TLI[7]*XLEN)
+result <- (~RT & ~RA & ~RB & TLI[0]*64) | # 64 copies of TLI[0]
+          (~RT & ~RA &  RB & TLI[1]*64) | # ...
+          (~RT &  RA & ~RB & TLI[2]*64) |
+          (~RT &  RA &  RB & TLI[3]*64) |
+          ( RT & ~RA & ~RB & TLI[4]*64) |
+          ( RT & ~RA &  RB & TLI[5]*64) |
+          ( RT &  RA & ~RB & TLI[6]*64) | # ...
+          ( RT &  RA &  RB & TLI[7]*64)   # 64 copies of TLI[7]
 RT <- result
 ```
 
-For each integer value i, 0 to XLEN-1, do the following.
+For each integer value i, 0 to 63, do the following.
 
     Let j be the value of the concatenation of the
     contents of bit i of RT, bit i of RB, bit i of RT.
@@ -198,6 +198,8 @@ For each integer value i, 0 to XLEN-1, do the following.
     Functions," on page 968 for the equivalent function
     evaluated by this instruction for any given value of TLI.
 
+Programmer's Note: this is a Read-Modify-Write instruction on RT.
+
 Special registers altered:
 
 ```
@@ -210,29 +212,55 @@ CR0                    (if Rc=1)
 
 # Condition Register Ternary Logic Immediate
 
-CRB-form
-
 Add this section to Book I 2.5.1
 
+CRB-form
+
 * `crternlogi BF, BFA, BFB, BFC, TLI, msk`
 
-| 0.5| 6-8 | 9-11 | 12-14 | 15-17 | 18-20 | 21-28 | 29-30 | 31  | Form     |
-|----|-----|------|-------|-------|-------|-------|-------|-----|----------|
-| PO | BF  | BFA  | BFB   | BFC   | msk   |  TLI  |  XO   | msk | CRB-Form |
+| 0.5|6.8 |9.10|11.13|14.15|16.18|19.25|26.30| 31| Form     |
+|----|----|----|-----|-----|-----|-----|-----|---|----------|
+| NN | BF | msk|BFA  | msk | BFB | TLI | XO  |TLI| CRB-Form |
+
+| 0.5| 6-8 | 9-11 | 12-14 | 15-17 | 18-20 | 21-28 | 29-30 | 31  |
+|----|-----|------|-------|-------|-------|-------|-------|-----|
+| PO | BF  | BFA  | BFB   | BFC   | msk   |  TLI  |  XO   | msk |
 
 Pseudocode:
 
 ```
-a <- CR[4*BFA+32:4*BFA+35]
-b <- CR[4*BFB+32:4*BFB+35]
-c <- CR[4*BFC+32:4*BFC+35]
+a <- CR[4*BF+32:4*BFA+35]
+b <- CR[4*BFA+32:4*BFB+35]
+c <- CR[4*BFB+32:4*BFC+35]
+ternary <- (~a & ~b & ~c & TLI[0]*4) | # 4 copies of TLI[0]
+           (~a & ~b &  c & TLI[1]*4) | # 4 copies of TLI[1]
+           (~a &  b & ~c & TLI[2]*4) | # ...
+           (~a &  b &  c & TLI[3]*4) |
+           ( a & ~b & ~c & TLI[4]*4) |
+           ( a & ~b &  c & TLI[5]*4) |
+           ( a &  b & ~c & TLI[6]*4) | # ...
+           ( a &  b &  c & TLI[7]*4))  # 4 copies of TLI[7]
 do i = 0 to 3
-    idx <- a[i] || b[i] || c[i]  # compute index from current bits
-    result <- TLI[7 - idx]  # subtract from 7 to index in LSB0 order
     if msk[i] = 1 then
-        CR[4*BF+32+i] <- result
+        CR[4*BF+32+i] <- ternary[i]
 ```
 
+For each integer value i, 0 to 3, do the following.
+
+    Let j be the value of the concatenation of the
+    contents of bit i of CR Field BF, bit i of CR Field BFA,
+    bit i of CR Field BFB.
+
+    If bit i of msk is set to 1 then the value of bit j of TLI
+    is placed into bit i of CR Field BF.
+
+    Otherwise, if bit i of msk is a zero then bit i of
+    CR Field BF is unchanged.
+
+    See Table 145, "xxeval(A, B, C, TLI) Equivalent
+    Functions," on page 968 for the equivalent function
+    evaluated by this instruction for any given value of TLI.
+
 Special registers altered:
 
 ```