add srcstep and correct PC-advancing during Sub-PC looping in ISACaller
[soc.git] / src / soc / decoder / isa / caller.py
index a75dc3fa7e4a127e273d1fa981d6967f6a693c8c..4a38a1ede376a61c3402c20b46715dabfe4b92ce 100644 (file)
+# SPDX-License-Identifier: LGPLv3+
+# Copyright (C) 2020, 2021 Luke Kenneth Casson Leighton <lkcl@lkcl.net>
+# Copyright (C) 2020 Michael Nolan
+# Funded by NLnet http://nlnet.nl
+"""core of the python-based POWER9 simulator
+
+this is part of a cycle-accurate POWER9 simulator.  its primary purpose is
+not speed, it is for both learning and educational purposes, as well as
+a method of verifying the HDL.
+
+related bugs:
+
+* https://bugs.libre-soc.org/show_bug.cgi?id=424
+"""
+
+from nmigen.back.pysim import Settle
 from functools import wraps
+from copy import copy
 from soc.decoder.orderedset import OrderedSet
-from soc.decoder.selectable_int import SelectableInt, selectconcat
+from soc.decoder.selectable_int import (FieldSelectableInt, SelectableInt,
+                                        selectconcat)
+from soc.decoder.power_enums import (spr_dict, spr_byname, XER_bits,
+                                     insns, MicrOp, In1Sel, In2Sel, In3Sel,
+                                     OutSel)
+from soc.decoder.helpers import exts, gtu, ltu, undefined
+from soc.consts import PIb, MSRb  # big-endian (PowerISA versions)
+from soc.decoder.power_svp64 import SVP64RM, decode_extra
+
+from collections import namedtuple
+import math
+import sys
+
+instruction_info = namedtuple('instruction_info',
+                              'func read_regs uninit_regs write_regs ' +
+                              'special_regs op_fields form asmregs')
+
+special_sprs = {
+    'LR': 8,
+    'CTR': 9,
+    'TAR': 815,
+    'XER': 1,
+    'VRSAVE': 256}
+
+
+def swap_order(x, nbytes):
+    x = x.to_bytes(nbytes, byteorder='little')
+    x = int.from_bytes(x, byteorder='big', signed=False)
+    return x
+
+
+REG_SORT_ORDER = {
+    # TODO (lkcl): adjust other registers that should be in a particular order
+    # probably CA, CA32, and CR
+    "RT": 0,
+    "RA": 0,
+    "RB": 0,
+    "RS": 0,
+    "CR": 0,
+    "LR": 0,
+    "CTR": 0,
+    "TAR": 0,
+    "CA": 0,
+    "CA32": 0,
+    "MSR": 0,
+
+    "overflow": 1,
+}
+
 
 def create_args(reglist, extra=None):
-    args = OrderedSet()
-    for reg in reglist:
-        args.add(reg)
-    args = list(args)
-    if extra:
-        args = [extra] + args
-    return args
+    retval = list(OrderedSet(reglist))
+    retval.sort(key=lambda reg: REG_SORT_ORDER[reg])
+    if extra is not None:
+        return [extra] + retval
+    return retval
+
 
 class Mem:
 
-    def __init__(self):
-        self.mem = []
-        for i in range(128):
-            self.mem.append(i)
+    def __init__(self, row_bytes=8, initial_mem=None):
+        self.mem = {}
+        self.bytes_per_word = row_bytes
+        self.word_log2 = math.ceil(math.log2(row_bytes))
+        print("Sim-Mem", initial_mem, self.bytes_per_word, self.word_log2)
+        if not initial_mem:
+            return
+
+        # different types of memory data structures recognised (for convenience)
+        if isinstance(initial_mem, list):
+            initial_mem = (0, initial_mem)
+        if isinstance(initial_mem, tuple):
+            startaddr, mem = initial_mem
+            initial_mem = {}
+            for i, val in enumerate(mem):
+                initial_mem[startaddr + row_bytes*i] = (val, row_bytes)
+
+        for addr, (val, width) in initial_mem.items():
+            #val = swap_order(val, width)
+            self.st(addr, val, width, swap=False)
+
+    def _get_shifter_mask(self, wid, remainder):
+        shifter = ((self.bytes_per_word - wid) - remainder) * \
+            8  # bits per byte
+        # XXX https://bugs.libre-soc.org/show_bug.cgi?id=377
+        # BE/LE mode?
+        shifter = remainder * 8
+        mask = (1 << (wid * 8)) - 1
+        print("width,rem,shift,mask", wid, remainder, hex(shifter), hex(mask))
+        return shifter, mask
+
+    # TODO: Implement ld/st of lesser width
+    def ld(self, address, width=8, swap=True, check_in_mem=False):
+        print("ld from addr 0x{:x} width {:d}".format(address, width))
+        remainder = address & (self.bytes_per_word - 1)
+        address = address >> self.word_log2
+        assert remainder & (width - 1) == 0, "Unaligned access unsupported!"
+        if address in self.mem:
+            val = self.mem[address]
+        elif check_in_mem:
+            return None
+        else:
+            val = 0
+        print("mem @ 0x{:x} rem {:d} : 0x{:x}".format(address, remainder, val))
+
+        if width != self.bytes_per_word:
+            shifter, mask = self._get_shifter_mask(width, remainder)
+            print("masking", hex(val), hex(mask << shifter), shifter)
+            val = val & (mask << shifter)
+            val >>= shifter
+        if swap:
+            val = swap_order(val, width)
+        print("Read 0x{:x} from addr 0x{:x}".format(val, address))
+        return val
+
+    def st(self, addr, v, width=8, swap=True):
+        staddr = addr
+        remainder = addr & (self.bytes_per_word - 1)
+        addr = addr >> self.word_log2
+        print("Writing 0x{:x} to ST 0x{:x} "
+              "memaddr 0x{:x}/{:x}".format(v, staddr, addr, remainder, swap))
+        assert remainder & (width - 1) == 0, "Unaligned access unsupported!"
+        if swap:
+            v = swap_order(v, width)
+        if width != self.bytes_per_word:
+            if addr in self.mem:
+                val = self.mem[addr]
+            else:
+                val = 0
+            shifter, mask = self._get_shifter_mask(width, remainder)
+            val &= ~(mask << shifter)
+            val |= v << shifter
+            self.mem[addr] = val
+        else:
+            self.mem[addr] = v
+        print("mem @ 0x{:x}: 0x{:x}".format(addr, self.mem[addr]))
 
     def __call__(self, addr, sz):
-        res = []
-        for s in range(sz): # TODO: big/little-end
-            res.append(SelectableInt(self.mem[addr.value + s], 8))
-        print ("memread", addr, sz, res)
-        return selectconcat(*res)
+        val = self.ld(addr.value, sz, swap=False)
+        print("memread", addr, sz, val)
+        return SelectableInt(val, sz*8)
 
     def memassign(self, addr, sz, val):
-        print ("memassign", addr, sz, val)
-        for s in range(sz):
-            byte = (val.value) >> (s*8) & 0xff # TODO: big/little-end
-            self.mem[addr.value + s] = byte
+        print("memassign", addr, sz, val)
+        self.st(addr.value, val.value, sz, swap=False)
 
 
 class GPR(dict):
-    def __init__(self, decoder, regfile):
+    def __init__(self, decoder, isacaller, svstate, regfile):
         dict.__init__(self)
         self.sd = decoder
+        self.isacaller = isacaller
+        self.svstate = svstate
         for i in range(32):
             self[i] = SelectableInt(regfile[i], 64)
 
@@ -46,7 +180,7 @@ class GPR(dict):
         self.form = form
 
     def getz(self, rnum):
-        #rnum = rnum.value # only SelectableInt allowed
+        # rnum = rnum.value # only SelectableInt allowed
         print("GPR getzero", rnum)
         if rnum == 0:
             return SelectableInt(0, 64)
@@ -58,44 +192,849 @@ class GPR(dict):
         return rnum
 
     def ___getitem__(self, attr):
-        print("GPR getitem", attr)
+        """ XXX currently not used
+        """
         rnum = self._get_regnum(attr)
+        offs = self.svstate.srcstep
+        print("GPR getitem", attr, rnum, "srcoffs", offs)
         return self.regfile[rnum]
 
+    def dump(self):
+        for i in range(0, len(self), 8):
+            s = []
+            for j in range(8):
+                s.append("%08x" % self[i+j].value)
+            s = ' '.join(s)
+            print("reg", "%2d" % i, s)
+
+
+class PC:
+    def __init__(self, pc_init=0):
+        self.CIA = SelectableInt(pc_init, 64)
+        self.NIA = self.CIA + SelectableInt(4, 64) # only true for v3.0B!
+
+    def update_nia(self, is_svp64):
+        increment = 8 if is_svp64 else 4
+        self.NIA = self.CIA + SelectableInt(increment, 64)
+
+    def update(self, namespace, is_svp64):
+        """updates the program counter (PC) by 4 if v3.0B mode or 8 if SVP64
+        """
+        self.CIA = namespace['NIA'].narrow(64)
+        self.update_nia(is_svp64)
+        namespace['CIA'] = self.CIA
+        namespace['NIA'] = self.NIA
+
+
+# Simple-V: see https://libre-soc.org/openpower/sv
+class SVP64State:
+    def __init__(self, init=0):
+        self.spr = SelectableInt(init, 32)
+        # fields of SVSTATE, see https://libre-soc.org/openpower/sv/sprs/
+        self.maxvl = FieldSelectableInt(self.spr, tuple(range(0,7)))
+        self.vl = FieldSelectableInt(self.spr, tuple(range(7,14)))
+        self.srcstep = FieldSelectableInt(self.spr, tuple(range(14,21)))
+        self.dststep = FieldSelectableInt(self.spr, tuple(range(21,28)))
+        self.subvl = FieldSelectableInt(self.spr, tuple(range(28,30)))
+        self.svstep = FieldSelectableInt(self.spr, tuple(range(30,32)))
+
+
+# SVP64 ReMap field
+class SVP64RMFields:
+    def __init__(self, init=0):
+        self.spr = SelectableInt(init, 24)
+        # SVP64 RM fields: see https://libre-soc.org/openpower/sv/svp64/
+        self.mmode = FieldSelectableInt(self.spr, [0])
+        self.mask = FieldSelectableInt(self.spr, tuple(range(1,4)))
+        self.elwidth = FieldSelectableInt(self.spr, tuple(range(4,6)))
+        self.ewsrc = FieldSelectableInt(self.spr, tuple(range(6,8)))
+        self.subvl = FieldSelectableInt(self.spr, tuple(range(8,10)))
+        self.extra = FieldSelectableInt(self.spr, tuple(range(10,19)))
+        self.mode = FieldSelectableInt(self.spr, tuple(range(19,24)))
+
+
+# SVP64 Prefix fields: see https://libre-soc.org/openpower/sv/svp64/
+class SVP64PrefixFields:
+    def __init__(self):
+        self.insn = SelectableInt(0, 32)
+        # 6 bit major opcode EXT001, 2 bits "identifying" (7, 9), 24 SV ReMap
+        self.major = FieldSelectableInt(self.insn, tuple(range(0,6)))
+        self.pid = FieldSelectableInt(self.insn, (7, 9)) # must be 0b11
+        rmfields = [6, 8] + list(range(10,32)) # SVP64 24-bit RM (ReMap)
+        self.rm = FieldSelectableInt(self.insn, rmfields)
+
+
+class SPR(dict):
+    def __init__(self, dec2, initial_sprs={}):
+        self.sd = dec2
+        dict.__init__(self)
+        for key, v in initial_sprs.items():
+            if isinstance(key, SelectableInt):
+                key = key.value
+            key = special_sprs.get(key, key)
+            if isinstance(key, int):
+                info = spr_dict[key]
+            else:
+                info = spr_byname[key]
+            if not isinstance(v, SelectableInt):
+                v = SelectableInt(v, info.length)
+            self[key] = v
+
+    def __getitem__(self, key):
+        print("get spr", key)
+        print("dict", self.items())
+        # if key in special_sprs get the special spr, otherwise return key
+        if isinstance(key, SelectableInt):
+            key = key.value
+        if isinstance(key, int):
+            key = spr_dict[key].SPR
+        key = special_sprs.get(key, key)
+        if key == 'HSRR0':  # HACK!
+            key = 'SRR0'
+        if key == 'HSRR1':  # HACK!
+            key = 'SRR1'
+        if key in self:
+            res = dict.__getitem__(self, key)
+        else:
+            if isinstance(key, int):
+                info = spr_dict[key]
+            else:
+                info = spr_byname[key]
+            dict.__setitem__(self, key, SelectableInt(0, info.length))
+            res = dict.__getitem__(self, key)
+        print("spr returning", key, res)
+        return res
+
+    def __setitem__(self, key, value):
+        if isinstance(key, SelectableInt):
+            key = key.value
+        if isinstance(key, int):
+            key = spr_dict[key].SPR
+            print("spr key", key)
+        key = special_sprs.get(key, key)
+        if key == 'HSRR0':  # HACK!
+            self.__setitem__('SRR0', value)
+        if key == 'HSRR1':  # HACK!
+            self.__setitem__('SRR1', value)
+        print("setting spr", key, value)
+        dict.__setitem__(self, key, value)
+
+    def __call__(self, ridx):
+        return self[ridx]
+
+def get_pdecode_idx_in(dec2, name):
+    op = dec2.dec.op
+    in1_sel = yield op.in1_sel
+    in2_sel = yield op.in2_sel
+    in3_sel = yield op.in3_sel
+    # get the IN1/2/3 from the decoder (includes SVP64 remap and isvec)
+    in1 = yield dec2.e.read_reg1.data
+    in2 = yield dec2.e.read_reg2.data
+    in3 = yield dec2.e.read_reg3.data
+    in1_isvec = yield dec2.in1_isvec
+    in2_isvec = yield dec2.in2_isvec
+    in3_isvec = yield dec2.in3_isvec
+    print ("get_pdecode_idx", in1_sel, In1Sel.RA.value, in1, in1_isvec)
+    # identify which regnames map to in1/2/3
+    if name == 'RA':
+        if (in1_sel == In1Sel.RA.value or
+            (in1_sel == In1Sel.RA_OR_ZERO.value and in1 != 0)):
+            return in1, in1_isvec
+        if in1_sel == In1Sel.RA_OR_ZERO.value:
+            return in1, in1_isvec
+    elif name == 'RB':
+        if in2_sel == In2Sel.RB.value:
+            return in2, in2_isvec
+        if in3_sel == In3Sel.RB.value:
+            return in3, in3_isvec
+    # XXX TODO, RC doesn't exist yet!
+    elif name == 'RC':
+        assert False, "RC does not exist yet"
+    elif name == 'RS':
+        if in1_sel == In1Sel.RS.value:
+            return in1, in1_isvec
+        if in2_sel == In2Sel.RS.value:
+            return in2, in2_isvec
+        if in3_sel == In3Sel.RS.value:
+            return in3, in3_isvec
+    return None, False
+
+
+def get_pdecode_idx_out(dec2, name):
+    op = dec2.dec.op
+    out_sel = yield op.out_sel
+    # get the IN1/2/3 from the decoder (includes SVP64 remap and isvec)
+    out = yield dec2.e.write_reg.data
+    o_isvec = yield dec2.o_isvec
+    print ("get_pdecode_idx_out", out_sel, OutSel.RA.value, out, o_isvec)
+    # identify which regnames map to out / o2
+    if name == 'RA':
+        if out_sel == OutSel.RA.value:
+            return out, o_isvec
+    elif name == 'RT':
+        if out_sel == OutSel.RT.value:
+            return out, o_isvec
+    print ("get_pdecode_idx_out not found", name)
+    return None, False
+
+
+# XXX TODO
+def get_pdecode_idx_out2(dec2, name):
+    op = dec2.dec.op
+    print ("TODO: get_pdecode_idx_out2", name)
+    return None, False
+
 
 class ISACaller:
     # decoder2 - an instance of power_decoder2
     # regfile - a list of initial values for the registers
-    def __init__(self, decoder2, regfile):
-        self.gpr = GPR(decoder2, regfile)
-        self.mem = Mem()
-        self.namespace = {'GPR': self.gpr,
-                          'MEM': self.mem,
-                          'memassign': self.memassign
-                          }
-        self.decoder = decoder2
+    # initial_{etc} - initial values for SPRs, Condition Register, Mem, MSR
+    # respect_pc - tracks the program counter.  requires initial_insns
+    def __init__(self, decoder2, regfile, initial_sprs=None, initial_cr=0,
+                 initial_mem=None, initial_msr=0,
+                 initial_svstate=0,
+                 initial_insns=None, respect_pc=False,
+                 disassembly=None,
+                 initial_pc=0,
+                 bigendian=False):
+
+        self.bigendian = bigendian
+        self.halted = False
+        self.is_svp64_mode = False
+        self.respect_pc = respect_pc
+        if initial_sprs is None:
+            initial_sprs = {}
+        if initial_mem is None:
+            initial_mem = {}
+        if initial_insns is None:
+            initial_insns = {}
+            assert self.respect_pc == False, "instructions required to honor pc"
+
+        print("ISACaller insns", respect_pc, initial_insns, disassembly)
+        print("ISACaller initial_msr", initial_msr)
+
+        # "fake program counter" mode (for unit testing)
+        self.fake_pc = 0
+        disasm_start = 0
+        if not respect_pc:
+            if isinstance(initial_mem, tuple):
+                self.fake_pc = initial_mem[0]
+                disasm_start = self.fake_pc
+        else:
+            disasm_start = initial_pc
+
+        # disassembly: we need this for now (not given from the decoder)
+        self.disassembly = {}
+        if disassembly:
+            for i, code in enumerate(disassembly):
+                self.disassembly[i*4 + disasm_start] = code
+
+        # set up registers, instruction memory, data memory, PC, SPRs, MSR
+        self.svp64rm = SVP64RM()
+        if isinstance(initial_svstate, int):
+            initial_svstate = SVP64State(initial_svstate)
+        self.svstate = initial_svstate
+        self.gpr = GPR(decoder2, self, self.svstate, regfile)
+        self.mem = Mem(row_bytes=8, initial_mem=initial_mem)
+        self.imem = Mem(row_bytes=4, initial_mem=initial_insns)
+        self.pc = PC()
+        self.spr = SPR(decoder2, initial_sprs)
+        self.msr = SelectableInt(initial_msr, 64)  # underlying reg
+
+        # TODO, needed here:
+        # FPR (same as GPR except for FP nums)
+        # 4.2.2 p124 FPSCR (definitely "separate" - not in SPR)
+        #            note that mffs, mcrfs, mtfsf "manage" this FPSCR
+        # 2.3.1 CR (and sub-fields CR0..CR6 - CR0 SO comes from XER.SO)
+        #         note that mfocrf, mfcr, mtcr, mtocrf, mcrxrx "manage" CRs
+        #         -- Done
+        # 2.3.2 LR   (actually SPR #8) -- Done
+        # 2.3.3 CTR  (actually SPR #9) -- Done
+        # 2.3.4 TAR  (actually SPR #815)
+        # 3.2.2 p45 XER  (actually SPR #1) -- Done
+        # 3.2.3 p46 p232 VRSAVE (actually SPR #256)
+
+        # create CR then allow portions of it to be "selectable" (below)
+        #rev_cr = int('{:016b}'.format(initial_cr)[::-1], 2)
+        self.cr = SelectableInt(initial_cr, 64)  # underlying reg
+        #self.cr = FieldSelectableInt(self._cr, list(range(32, 64)))
+
+        # "undefined", just set to variable-bit-width int (use exts "max")
+        #self.undefined = SelectableInt(0, 256)  # TODO, not hard-code 256!
+
+        self.namespace = {}
+        self.namespace.update(self.spr)
+        self.namespace.update({'GPR': self.gpr,
+                               'MEM': self.mem,
+                               'SPR': self.spr,
+                               'memassign': self.memassign,
+                               'NIA': self.pc.NIA,
+                               'CIA': self.pc.CIA,
+                               'CR': self.cr,
+                               'MSR': self.msr,
+                               'undefined': undefined,
+                               'mode_is_64bit': True,
+                               'SO': XER_bits['SO']
+                               })
+
+        # update pc to requested start point
+        self.set_pc(initial_pc)
+
+        # field-selectable versions of Condition Register TODO check bitranges?
+        self.crl = []
+        for i in range(8):
+            bits = tuple(range(i*4+32, (i+1)*4+32))  # errr... maybe?
+            _cr = FieldSelectableInt(self.cr, bits)
+            self.crl.append(_cr)
+            self.namespace["CR%d" % i] = _cr
+
+        self.decoder = decoder2.dec
+        self.dec2 = decoder2
+
+    def TRAP(self, trap_addr=0x700, trap_bit=PIb.TRAP):
+        print("TRAP:", hex(trap_addr), hex(self.namespace['MSR'].value))
+        # store CIA(+4?) in SRR0, set NIA to 0x700
+        # store MSR in SRR1, set MSR to um errr something, have to check spec
+        self.spr['SRR0'].value = self.pc.CIA.value
+        self.spr['SRR1'].value = self.namespace['MSR'].value
+        self.trap_nia = SelectableInt(trap_addr, 64)
+        self.spr['SRR1'][trap_bit] = 1  # change *copy* of MSR in SRR1
+
+        # set exception bits.  TODO: this should, based on the address
+        # in figure 66 p1065 V3.0B and the table figure 65 p1063 set these
+        # bits appropriately.  however it turns out that *for now* in all
+        # cases (all trap_addrs) the exact same thing is needed.
+        self.msr[MSRb.IR] = 0
+        self.msr[MSRb.DR] = 0
+        self.msr[MSRb.FE0] = 0
+        self.msr[MSRb.FE1] = 0
+        self.msr[MSRb.EE] = 0
+        self.msr[MSRb.RI] = 0
+        self.msr[MSRb.SF] = 1
+        self.msr[MSRb.TM] = 0
+        self.msr[MSRb.VEC] = 0
+        self.msr[MSRb.VSX] = 0
+        self.msr[MSRb.PR] = 0
+        self.msr[MSRb.FP] = 0
+        self.msr[MSRb.PMM] = 0
+        self.msr[MSRb.TEs] = 0
+        self.msr[MSRb.TEe] = 0
+        self.msr[MSRb.UND] = 0
+        self.msr[MSRb.LE] = 1
 
     def memassign(self, ea, sz, val):
         self.mem.memassign(ea, sz, val)
 
+    def prep_namespace(self, formname, op_fields):
+        # TODO: get field names from form in decoder*1* (not decoder2)
+        # decoder2 is hand-created, and decoder1.sigform is auto-generated
+        # from spec
+        # then "yield" fields only from op_fields rather than hard-coded
+        # list, here.
+        fields = self.decoder.sigforms[formname]
+        for name in op_fields:
+            if name == 'spr':
+                sig = getattr(fields, name.upper())
+            else:
+                sig = getattr(fields, name)
+            val = yield sig
+            # these are all opcode fields involved in index-selection of CR,
+            # and need to do "standard" arithmetic.  CR[BA+32] for example
+            # would, if using SelectableInt, only be 5-bit.
+            if name in ['BF', 'BFA', 'BC', 'BA', 'BB', 'BT', 'BI']:
+                self.namespace[name] = val
+            else:
+                self.namespace[name] = SelectableInt(val, sig.width)
+
+        self.namespace['XER'] = self.spr['XER']
+        self.namespace['CA'] = self.spr['XER'][XER_bits['CA']].value
+        self.namespace['CA32'] = self.spr['XER'][XER_bits['CA32']].value
+
+    def handle_carry_(self, inputs, outputs, already_done):
+        inv_a = yield self.dec2.e.do.invert_in
+        if inv_a:
+            inputs[0] = ~inputs[0]
+
+        imm_ok = yield self.dec2.e.do.imm_data.ok
+        if imm_ok:
+            imm = yield self.dec2.e.do.imm_data.data
+            inputs.append(SelectableInt(imm, 64))
+        assert len(outputs) >= 1
+        print("outputs", repr(outputs))
+        if isinstance(outputs, list) or isinstance(outputs, tuple):
+            output = outputs[0]
+        else:
+            output = outputs
+        gts = []
+        for x in inputs:
+            print("gt input", x, output)
+            gt = (gtu(x, output))
+            gts.append(gt)
+        print(gts)
+        cy = 1 if any(gts) else 0
+        print("CA", cy, gts)
+        if not (1 & already_done):
+            self.spr['XER'][XER_bits['CA']] = cy
+
+        print("inputs", already_done, inputs)
+        # 32 bit carry
+        # ARGH... different for OP_ADD... *sigh*...
+        op = yield self.dec2.e.do.insn_type
+        if op == MicrOp.OP_ADD.value:
+            res32 = (output.value & (1 << 32)) != 0
+            a32 = (inputs[0].value & (1 << 32)) != 0
+            if len(inputs) >= 2:
+                b32 = (inputs[1].value & (1 << 32)) != 0
+            else:
+                b32 = False
+            cy32 = res32 ^ a32 ^ b32
+            print("CA32 ADD", cy32)
+        else:
+            gts = []
+            for x in inputs:
+                print("input", x, output)
+                print("     x[32:64]", x, x[32:64])
+                print("     o[32:64]", output, output[32:64])
+                gt = (gtu(x[32:64], output[32:64])) == SelectableInt(1, 1)
+                gts.append(gt)
+            cy32 = 1 if any(gts) else 0
+            print("CA32", cy32, gts)
+        if not (2 & already_done):
+            self.spr['XER'][XER_bits['CA32']] = cy32
+
+    def handle_overflow(self, inputs, outputs, div_overflow):
+        if hasattr(self.dec2.e.do, "invert_in"):
+            inv_a = yield self.dec2.e.do.invert_in
+            if inv_a:
+                inputs[0] = ~inputs[0]
+
+        imm_ok = yield self.dec2.e.do.imm_data.ok
+        if imm_ok:
+            imm = yield self.dec2.e.do.imm_data.data
+            inputs.append(SelectableInt(imm, 64))
+        assert len(outputs) >= 1
+        print("handle_overflow", inputs, outputs, div_overflow)
+        if len(inputs) < 2 and div_overflow is None:
+            return
+
+        # div overflow is different: it's returned by the pseudo-code
+        # because it's more complex than can be done by analysing the output
+        if div_overflow is not None:
+            ov, ov32 = div_overflow, div_overflow
+        # arithmetic overflow can be done by analysing the input and output
+        elif len(inputs) >= 2:
+            output = outputs[0]
+
+            # OV (64-bit)
+            input_sgn = [exts(x.value, x.bits) < 0 for x in inputs]
+            output_sgn = exts(output.value, output.bits) < 0
+            ov = 1 if input_sgn[0] == input_sgn[1] and \
+                output_sgn != input_sgn[0] else 0
+
+            # OV (32-bit)
+            input32_sgn = [exts(x.value, 32) < 0 for x in inputs]
+            output32_sgn = exts(output.value, 32) < 0
+            ov32 = 1 if input32_sgn[0] == input32_sgn[1] and \
+                output32_sgn != input32_sgn[0] else 0
+
+        self.spr['XER'][XER_bits['OV']] = ov
+        self.spr['XER'][XER_bits['OV32']] = ov32
+        so = self.spr['XER'][XER_bits['SO']]
+        so = so | ov
+        self.spr['XER'][XER_bits['SO']] = so
+
+    def handle_comparison(self, outputs):
+        out = outputs[0]
+        assert isinstance(out, SelectableInt), \
+            "out zero not a SelectableInt %s" % repr(outputs)
+        print("handle_comparison", out.bits, hex(out.value))
+        # TODO - XXX *processor* in 32-bit mode
+        # https://bugs.libre-soc.org/show_bug.cgi?id=424
+        # if is_32bit:
+        #    o32 = exts(out.value, 32)
+        #    print ("handle_comparison exts 32 bit", hex(o32))
+        out = exts(out.value, out.bits)
+        print("handle_comparison exts", hex(out))
+        zero = SelectableInt(out == 0, 1)
+        positive = SelectableInt(out > 0, 1)
+        negative = SelectableInt(out < 0, 1)
+        SO = self.spr['XER'][XER_bits['SO']]
+        print("handle_comparison SO", SO)
+        cr_field = selectconcat(negative, positive, zero, SO)
+        self.crl[0].eq(cr_field)
+
+    def set_pc(self, pc_val):
+        self.namespace['NIA'] = SelectableInt(pc_val, 64)
+        self.pc.update(self.namespace, self.is_svp64_mode)
+
+    def setup_one(self):
+        """set up one instruction
+        """
+        if self.respect_pc:
+            pc = self.pc.CIA.value
+        else:
+            pc = self.fake_pc
+        self._pc = pc
+        ins = self.imem.ld(pc, 4, False, True)
+        if ins is None:
+            raise KeyError("no instruction at 0x%x" % pc)
+        print("setup: 0x%x 0x%x %s" % (pc, ins & 0xffffffff, bin(ins)))
+        print("CIA NIA", self.respect_pc, self.pc.CIA.value, self.pc.NIA.value)
+
+        yield self.dec2.sv_rm.eq(0)
+        yield self.dec2.dec.raw_opcode_in.eq(ins & 0xffffffff)
+        yield self.dec2.dec.bigendian.eq(self.bigendian)
+        yield self.dec2.state.msr.eq(self.msr.value)
+        yield self.dec2.state.pc.eq(pc)
+
+        # SVP64.  first, check if the opcode is EXT001, and SVP64 id bits set
+        yield Settle()
+        opcode = yield self.dec2.dec.opcode_in
+        pfx = SVP64PrefixFields() # TODO should probably use SVP64PrefixDecoder
+        pfx.insn.value = opcode
+        major = pfx.major.asint(msb0=True) # MSB0 inversion
+        print ("prefix test: opcode:", major, bin(major),
+                pfx.insn[7] == 0b1, pfx.insn[9] == 0b1)
+        self.is_svp64_mode = ((major == 0b000001) and
+                              pfx.insn[7].value == 0b1 and
+                              pfx.insn[9].value == 0b1)
+        self.pc.update_nia(self.is_svp64_mode)
+        if not self.is_svp64_mode:
+            return
+
+        # in SVP64 mode.  decode/print out svp64 prefix, get v3.0B instruction
+        print ("svp64.rm", bin(pfx.rm.asint(msb0=True)))
+        print ("    svstate.vl", self.svstate.vl.asint(msb0=True))
+        print ("    svstate.mvl", self.svstate.maxvl.asint(msb0=True))
+        sv_rm = pfx.rm.asint()
+        ins = self.imem.ld(pc+4, 4, False, True)
+        print("     svsetup: 0x%x 0x%x %s" % (pc+4, ins & 0xffffffff, bin(ins)))
+        yield self.dec2.dec.raw_opcode_in.eq(ins & 0xffffffff) # v3.0B suffix
+        yield self.dec2.sv_rm.eq(sv_rm)                        # svp64 prefix
+        yield Settle()
+
+    def execute_one(self):
+        """execute one instruction
+        """
+        # get the disassembly code for this instruction
+        if self.is_svp64_mode:
+            code = self.disassembly[self._pc+4]
+            print("    svp64 sim-execute", hex(self._pc), code)
+        else:
+            code = self.disassembly[self._pc]
+            print("sim-execute", hex(self._pc), code)
+        opname = code.split(' ')[0]
+        yield from self.call(opname)
+
+        # don't use this except in special circumstances
+        if not self.respect_pc:
+            self.fake_pc += 4
+
+        print("execute one, CIA NIA", self.pc.CIA.value, self.pc.NIA.value)
+
+    def get_assembly_name(self):
+        # TODO, asmregs is from the spec, e.g. add RT,RA,RB
+        # see http://bugs.libre-riscv.org/show_bug.cgi?id=282
+        dec_insn = yield self.dec2.e.do.insn
+        asmcode = yield self.dec2.dec.op.asmcode
+        print("get assembly name asmcode", asmcode, hex(dec_insn))
+        asmop = insns.get(asmcode, None)
+        int_op = yield self.dec2.dec.op.internal_op
+
+        # sigh reconstruct the assembly instruction name
+        if hasattr(self.dec2.e.do, "oe"):
+            ov_en = yield self.dec2.e.do.oe.oe
+            ov_ok = yield self.dec2.e.do.oe.ok
+        else:
+            ov_en = False
+            ov_ok = False
+        if hasattr(self.dec2.e.do, "rc"):
+            rc_en = yield self.dec2.e.do.rc.rc
+            rc_ok = yield self.dec2.e.do.rc.ok
+        else:
+            rc_en = False
+            rc_ok = False
+        # grrrr have to special-case MUL op (see DecodeOE)
+        print("ov %d en %d rc %d en %d op %d" %
+              (ov_ok, ov_en, rc_ok, rc_en, int_op))
+        if int_op in [MicrOp.OP_MUL_H64.value, MicrOp.OP_MUL_H32.value]:
+            print("mul op")
+            if rc_en & rc_ok:
+                asmop += "."
+        else:
+            if not asmop.endswith("."):  # don't add "." to "andis."
+                if rc_en & rc_ok:
+                    asmop += "."
+        if hasattr(self.dec2.e.do, "lk"):
+            lk = yield self.dec2.e.do.lk
+            if lk:
+                asmop += "l"
+        print("int_op", int_op)
+        if int_op in [MicrOp.OP_B.value, MicrOp.OP_BC.value]:
+            AA = yield self.dec2.dec.fields.FormI.AA[0:-1]
+            print("AA", AA)
+            if AA:
+                asmop += "a"
+        spr_msb = yield from self.get_spr_msb()
+        if int_op == MicrOp.OP_MFCR.value:
+            if spr_msb:
+                asmop = 'mfocrf'
+            else:
+                asmop = 'mfcr'
+        # XXX TODO: for whatever weird reason this doesn't work
+        # https://bugs.libre-soc.org/show_bug.cgi?id=390
+        if int_op == MicrOp.OP_MTCRF.value:
+            if spr_msb:
+                asmop = 'mtocrf'
+            else:
+                asmop = 'mtcrf'
+        return asmop
+
+    def get_spr_msb(self):
+        dec_insn = yield self.dec2.e.do.insn
+        return dec_insn & (1 << 20) != 0  # sigh - XFF.spr[-1]?
+
     def call(self, name):
-        function, read_regs, uninit_regs, write_regs = self.instrs[name]
-        input_names = create_args(read_regs | uninit_regs)
+        """call(opcode) - the primary execution point for instructions
+        """
+        name = name.strip()  # remove spaces if not already done so
+        if self.halted:
+            print("halted - not executing", name)
+            return
+
+        # TODO, asmregs is from the spec, e.g. add RT,RA,RB
+        # see http://bugs.libre-riscv.org/show_bug.cgi?id=282
+        asmop = yield from self.get_assembly_name()
+        print("call", name, asmop)
+
+        # check privileged
+        int_op = yield self.dec2.dec.op.internal_op
+        spr_msb = yield from self.get_spr_msb()
+
+        instr_is_privileged = False
+        if int_op in [MicrOp.OP_ATTN.value,
+                      MicrOp.OP_MFMSR.value,
+                      MicrOp.OP_MTMSR.value,
+                      MicrOp.OP_MTMSRD.value,
+                      # TODO: OP_TLBIE
+                      MicrOp.OP_RFID.value]:
+            instr_is_privileged = True
+        if int_op in [MicrOp.OP_MFSPR.value,
+                      MicrOp.OP_MTSPR.value] and spr_msb:
+            instr_is_privileged = True
+
+        print("is priv", instr_is_privileged, hex(self.msr.value),
+              self.msr[MSRb.PR])
+        # check MSR priv bit and whether op is privileged: if so, throw trap
+        if instr_is_privileged and self.msr[MSRb.PR] == 1:
+            self.TRAP(0x700, PIb.PRIV)
+            self.namespace['NIA'] = self.trap_nia
+            self.pc.update(self.namespace, self.is_svp64_mode)
+            return
+
+        # check halted condition
+        if name == 'attn':
+            self.halted = True
+            return
+
+        # check illegal instruction
+        illegal = False
+        if name not in ['mtcrf', 'mtocrf']:
+            illegal = name != asmop
+
+        if illegal:
+            print("illegal", name, asmop)
+            self.TRAP(0x700, PIb.ILLEG)
+            self.namespace['NIA'] = self.trap_nia
+            self.pc.update(self.namespace, self.is_svp64_mode)
+            print("name %s != %s - calling ILLEGAL trap, PC: %x" %
+                  (name, asmop, self.pc.CIA.value))
+            return
+
+        info = self.instrs[name]
+        yield from self.prep_namespace(info.form, info.op_fields)
+
+        # preserve order of register names
+        input_names = create_args(list(info.read_regs) +
+                                  list(info.uninit_regs))
         print(input_names)
 
+        # get SVP64 entry for the current instruction
+        sv_rm = self.svp64rm.instrs.get(name)
+        if sv_rm is not None:
+            dest_cr, src_cr, src_byname, dest_byname = decode_extra(sv_rm)
+        else:
+            dest_cr, src_cr, src_byname, dest_byname = False, False, {}, {}
+        print ("sv rm", sv_rm, dest_cr, src_cr, src_byname, dest_byname)
+
+        # get SVSTATE srcstep.  TODO: dststep (twin predication)
+        srcstep = self.svstate.srcstep.asint(msb0=True)
+
+        # main input registers (RT, RA ...)
         inputs = []
         for name in input_names:
-            regnum = yield getattr(self.decoder, name)
-            print(regnum)
-            inputs.append(self.gpr(regnum))
+            # using PowerDecoder2, first, find the decoder index.
+            # (mapping name RA RB RC RS to in1, in2, in3)
+            regnum, is_vec = yield from get_pdecode_idx_in(self.dec2, name)
+            if regnum is None:
+                # doing this is not part of svp64, it's because output
+                # registers, to be modified, need to be in the namespace.
+                regnum, is_vec = yield from get_pdecode_idx_out(self.dec2, name)
+            # here's where we go "vector".  TODO: zero-testing (RA_IS_ZERO)
+            if is_vec:
+                regnum += srcstep # TODO, elwidth overrides
+
+            # in case getting the register number is needed, _RA, _RB
+            regname = "_" + name
+            self.namespace[regname] = regnum
+            print('reading reg %s %d' % (name, regnum), is_vec)
+            reg_val = self.gpr(regnum)
+            inputs.append(reg_val)
+
+        # "special" registers
+        for special in info.special_regs:
+            if special in special_sprs:
+                inputs.append(self.spr[special])
+            else:
+                inputs.append(self.namespace[special])
+
+        # clear trap (trap) NIA
+        self.trap_nia = None
+
         print(inputs)
-        results = function(self, *inputs)
+        results = info.func(self, *inputs)
         print(results)
 
+        # "inject" decorator takes namespace from function locals: we need to
+        # overwrite NIA being overwritten (sigh)
+        if self.trap_nia is not None:
+            self.namespace['NIA'] = self.trap_nia
+
+        print("after func", self.namespace['CIA'], self.namespace['NIA'])
+
+        # detect if CA/CA32 already in outputs (sra*, basically)
+        already_done = 0
+        if info.write_regs:
+            output_names = create_args(info.write_regs)
+            for name in output_names:
+                if name == 'CA':
+                    already_done |= 1
+                if name == 'CA32':
+                    already_done |= 2
+
+        print("carry already done?", bin(already_done))
+        if hasattr(self.dec2.e.do, "output_carry"):
+            carry_en = yield self.dec2.e.do.output_carry
+        else:
+            carry_en = False
+        if carry_en:
+            yield from self.handle_carry_(inputs, results, already_done)
+
+        # detect if overflow was in return result
+        overflow = None
+        if info.write_regs:
+            for name, output in zip(output_names, results):
+                if name == 'overflow':
+                    overflow = output
+
+        if hasattr(self.dec2.e.do, "oe"):
+            ov_en = yield self.dec2.e.do.oe.oe
+            ov_ok = yield self.dec2.e.do.oe.ok
+        else:
+            ov_en = False
+            ov_ok = False
+        print("internal overflow", overflow, ov_en, ov_ok)
+        if ov_en & ov_ok:
+            yield from self.handle_overflow(inputs, results, overflow)
+
+        if hasattr(self.dec2.e.do, "rc"):
+            rc_en = yield self.dec2.e.do.rc.rc
+        else:
+            rc_en = False
+        if rc_en:
+            self.handle_comparison(results)
+
+        # svp64 loop can end early if the dest is scalar
+        svp64_dest_vector = False
+
+        # any modified return results?
+        if info.write_regs:
+            for name, output in zip(output_names, results):
+                if name == 'overflow':  # ignore, done already (above)
+                    continue
+                if isinstance(output, int):
+                    output = SelectableInt(output, 256)
+                if name in ['CA', 'CA32']:
+                    if carry_en:
+                        print("writing %s to XER" % name, output)
+                        self.spr['XER'][XER_bits[name]] = output.value
+                    else:
+                        print("NOT writing %s to XER" % name, output)
+                elif name in info.special_regs:
+                    print('writing special %s' % name, output, special_sprs)
+                    if name in special_sprs:
+                        self.spr[name] = output
+                    else:
+                        self.namespace[name].eq(output)
+                    if name == 'MSR':
+                        print('msr written', hex(self.msr.value))
+                else:
+                    regnum, is_vec = yield from get_pdecode_idx_out(self.dec2,
+                                                name)
+                    if regnum is None:
+                        # temporary hack for not having 2nd output
+                        regnum = yield getattr(self.decoder, name)
+                        is_vec = False
+                    # here's where we go "vector".
+                    if is_vec:
+                        regnum += srcstep # TODO, elwidth overrides
+                        svp64_dest_vector = True
+                    print('writing reg %d %s' % (regnum, str(output)), is_vec)
+                    if output.bits > 64:
+                        output = SelectableInt(output.value, 64)
+                    self.gpr[regnum] = output
+
+        # check if it is the SVSTATE.src/dest step that needs incrementing
+        # this is our Sub-Program-Counter loop from 0 to VL-1
+        if self.is_svp64_mode:
+            # XXX twin predication TODO
+            vl = self.svstate.vl.asint(msb0=True)
+            mvl = self.svstate.maxvl.asint(msb0=True)
+            srcstep = self.svstate.srcstep.asint(msb0=True)
+            print ("    svstate.vl", vl)
+            print ("    svstate.mvl", mvl)
+            print ("    svstate.srcstep", srcstep)
+            # check if srcstep needs incrementing by one, stop PC advancing
+            if svp64_dest_vector and srcstep != vl-1:
+                self.svstate.srcstep += SelectableInt(1, 7)
+                self.pc.NIA.value = self.pc.CIA.value
+                self.namespace['NIA'] = self.pc.NIA
+                print("end of sub-pc call", self.namespace['CIA'],
+                                     self.namespace['NIA'])
+                return # DO NOT allow PC to update whilst Sub-PC loop running
+            # reset to zero
+            self.svstate.srcstep[0:7] = 0
+            print ("    svstate.srcstep loop end (PC to update)")
+            self.pc.update_nia(self.is_svp64_mode)
+            self.namespace['NIA'] = self.pc.NIA
+
+        # UPDATE program counter
+        self.pc.update(self.namespace, self.is_svp64_mode)
+        print("end of call", self.namespace['CIA'], self.namespace['NIA'])
 
 
 def inject():
-    """ Decorator factory. """
+    """Decorator factory.
+
+    this decorator will "inject" variables into the function's namespace,
+    from the *dictionary* in self.namespace.  it therefore becomes possible
+    to make it look like a whole stack of variables which would otherwise
+    need "self." inserted in front of them (*and* for those variables to be
+    added to the instance) "appear" in the function.
+
+    "self.namespace['SI']" for example becomes accessible as just "SI" but
+    *only* inside the function, when decorated.
+    """
     def variable_injector(func):
         @wraps(func)
         def decorator(*args, **kwargs):
@@ -104,14 +1043,17 @@ def inject():
             except AttributeError:
                 func_globals = func.func_globals  # Earlier versions.
 
-            context = args[0].namespace
+            context = args[0].namespace  # variables to be injected
             saved_values = func_globals.copy()  # Shallow copy of dict.
             func_globals.update(context)
-
             result = func(*args, **kwargs)
+            print("globals after", func_globals['CIA'], func_globals['NIA'])
+            print("args[0]", args[0].namespace['CIA'],
+                  args[0].namespace['NIA'])
+            args[0].namespace = func_globals
             #exec (func.__code__, func_globals)
 
-            #finally:
+            # finally:
             #    func_globals = saved_values  # Undo changes.
 
             return result
@@ -119,4 +1061,3 @@ def inject():
         return decorator
 
     return variable_injector
-