From: Luke Kenneth Casson Leighton <lkcl@lkcl.net>
Date: Mon, 7 Oct 2019 15:27:50 +0000 (+0100)
Subject: add SHAPE / REMAP area to VBLOCK2
X-Git-Tag: convert-csv-opcode-to-binary~3874
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=5447a27b35bea28c036361ea8c1234ea0eca075e;p=libreriscv.git

add SHAPE / REMAP area to VBLOCK2
---

diff --git a/simple_v_extension/vblock_format.mdwn b/simple_v_extension/vblock_format.mdwn
index 680d747bd..6cad577b9 100644
--- a/simple_v_extension/vblock_format.mdwn
+++ b/simple_v_extension/vblock_format.mdwn
@@ -153,6 +153,28 @@ The swizzle table format is included here for convenience:
 
 Swizzle blocks are only accessible using the "VBLOCK2" format.
 
+# REMAP Area Format<a name="remap_format"></a>
+
+The REMAP area is divided into two areas:
+
+* Register-to-SHAPE.  This defines which registers have which shapes.
+  Each entry is 8-bits in length.
+* SHAPE Table entries.  These are 32-bits in length and are aligned
+  to (start on) a 16 bit boundary.
+
+REMAP Table Entries:
+
+| 7:5      | 4:0    |
+| -------- | ------ |
+| shapeidx | regnum |
+
+When both shapeidx and regnum are zero, this indicates the end of the
+REMAP Register-to-SHAPE section.  The REMAP Table section size is then
+aligned to a 16-bit boundary.  32-bit SHAPE Table Entries then fill the
+remainder of the REMAP area, and are indexed in order by shapeidx.
+
+In this way, multiple registers may share the same "shape" characteristics.
+
 # SHAPE Table Format<a name="shape_format"></a>
 
 The shape table format is included here for convenience:
diff --git a/simple_v_extension/vblock_format_table.mdwn b/simple_v_extension/vblock_format_table.mdwn
index 2c274a727..b3b6a6586 100644
--- a/simple_v_extension/vblock_format_table.mdwn
+++ b/simple_v_extension/vblock_format_table.mdwn
@@ -36,12 +36,26 @@ RISC-V ISA format.  Note that the length is 96+16\*nnnnn, not 192+
 
 VBLOCK2 extends the VBLOCK fields:
 
-| 15:12 | 11:10  | 9:8    | 7:5   | 4:0  |
-| ----- | -----  | ----   | ---   | ---- |
-| rsvd  | rplen2 | pplen2 | swlen | ilen |
+| 15   | 14:12 | 11:10  | 9:8    | 7:5   | 4:0  |
+| ---- | ----- | -----  | ----   | ---   | ---- |
+| rsvd | mapsz | rplen2 | pplen2 | swlen | ilen |
 
 * ilen is the instruction length (number of 16-bit blocks)
 * swlen specifies the number of "swizzle" blocks
 * rplen2 extends rplen by 2 bits
 * pplen2 extends pplen by 2 bits
-* 4 bits are reserved for additional tables (Matrices?)
+* mapsz indicates the size of the "remap" area.  See table below for size
+* 1 bit is reserved for extensions
+
+Mapsz to Remap size is in number of 16-bit blocks:
+
+| mapsz | remap size |
+| ----- | ---------- |
+| 0     | 0          |
+| 1     | 6          |
+| 2     | 7          |
+| 3     | 8          |
+| 4     | 10         |
+| 5     | 12         |
+| 6     | 14         |
+| 7     | 16         |