add beginnings of svp64 assembly translator

diff --git a/src/soc/sv/trans/svp64.py b/src/soc/sv/trans/svp64.py
new file mode 100644 (file)
index 0000000..541306f
--- /dev/null
+++ b/src/soc/sv/trans/svp64.py
@@ -0,0 +1,63 @@
+# SPDX-License-Identifier: LGPLv3+
+# Copyright (C) 2021 Luke Kenneth Casson Leighton <lkcl@lkcl.net>
+# Funded by NLnet http://nlnet.nl
+
+"""SVP64 OpenPOWER v3.0B assembly translator
+
+This class takes raw svp64 assembly mnemonics (aliases excluded) and
+creates an EXT001-encoded "svp64 prefix" followed by a v3.0B opcode.
+It is very simple
+"""
+
+from soc.decoder.pseudo.pagereader import ISA
+
+
+def is_CR_3bit(regname):
+    return regname in ['BF', 'BFA']
+
+def is_CR_5bit(regname):
+    return regname in ['BA', 'BB', 'BC', 'BI', 'BT']
+
+def is_GPR(regname):
+    return regname in ['RA', 'RB', 'RC', 'RS', 'RT']
+
+
+class SVP64:
+    def __init__(self, lst):
+        self.lst = lst
+        self.trans = self.translate(lst)
+
+    def __iter__(self):
+        for insn in self.trans:
+            yield insn
+
+    def translate(self, lst):
+        isa = ISA() # reads the v3.0B pseudo-code markdown files
+        res = []
+        for insn in lst:
+            # find first space, to get opcode
+            ls = insn.split(' ')
+            opcode = ls[0]
+            # now find opcode fields
+            fields = ''.join(ls[1:]).split(',')
+            fields = list(map(str.strip, fields))
+            print (opcode, fields)
+
+            # identify if is a svp64 mnemonic
+            if not opcode.startswith('sv.'):
+                res.append(insn) # unaltered
+                continue
+
+            # start working on decoding the svp64 op: sv.baseop.vec2.mode
+            opmodes = opcode.split(".")[1:] # strip leading "sv."
+            v30b_op = opmodes.pop(0)        # first is the v3.0B
+            if v30b_op not in isa.instr:
+                raise Exception("opcode %s of '%s' not supported" % \
+                                (v30b_op, insn))
+
+        return res
+
+if __name__ == '__main__':
+    isa = SVP64(['slw 3, 1, 4',
+                 'extsw 5, 3'])
+