From: Luke Kenneth Casson Leighton Date: Sat, 30 Jan 2021 00:17:20 +0000 (+0000) Subject: add first SVP64 7-bit register context decoder to PowerDecoder2 X-Git-Tag: convert-csv-opcode-to-binary~290 X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=63aeeaa31a60065b03421d3a5497327078d0b0e8;p=soc.git add first SVP64 7-bit register context decoder to PowerDecoder2 --- diff --git a/src/soc/decoder/power_decoder.py b/src/soc/decoder/power_decoder.py index 6712cd1d..bdad81ba 100644 --- a/src/soc/decoder/power_decoder.py +++ b/src/soc/decoder/power_decoder.py @@ -152,6 +152,8 @@ power_op_csvmap = {'function_unit': 'unit', 'sv_out': 'sv_out', 'sv_cr_in': 'sv_cr_in', 'sv_cr_out': 'sv_cr_out', + 'SV_Etype': 'SV_Etype', + 'SV_Ptype': 'SV_Ptype', 'cr_in': 'CR in', 'cr_out': 'CR out', 'ldst_len': 'ldst len', diff --git a/src/soc/decoder/power_decoder2.py b/src/soc/decoder/power_decoder2.py index 57d7e4fb..220258e0 100644 --- a/src/soc/decoder/power_decoder2.py +++ b/src/soc/decoder/power_decoder2.py @@ -22,7 +22,8 @@ from soc.decoder.power_decoder import create_pdecode from soc.decoder.power_enums import (MicrOp, CryIn, Function, CRInSel, CROutSel, LdstLen, In1Sel, In2Sel, In3Sel, - OutSel, SPR, RC, LDSTMode) + OutSel, SPR, RC, LDSTMode, + SVEXTRA, SVEtype) from soc.decoder.decode2execute1 import (Decode2ToExecute1Type, Data, Decode2ToOperand) from soc.sv.svp64 import SVP64Rec @@ -78,6 +79,77 @@ class SPRMap(Elaboratable): return m +class SVP64RegExtra(Elaboratable): + """SVP64RegExtra - decodes SVP64 Extra fields to determine reg extension + + incoming 5-bit GPR/FP is turned into a 7-bit and marked as scalar/vector + depending on info in one of the positions in the EXTRA field. + + designed so that "no change" to the 5-bit register number occurs if + SV either does not apply or the relevant EXTRA2/3 field bits are zero. + + see https://libre-soc.org/openpower/sv/svp64/ + """ + def __init__(self): + self.extra = Signal(10, reset_less=True) + self.etype = Signal(SVEtype, reset_less=True) # 2 or 3 bits + self.idx = Signal(SVEXTRA, reset_less=True) # which part of extra + self.reg_in = Signal(5) # incoming reg number (5 bits, RA, RB) + self.reg_out = Signal(7) # extra-augmented output (7 bits) + self.isvec = Signal(1) # reg is marked as vector if true + + def elaborate(self, platform): + m = Module() + comb = m.d.comb + + # first get the spec. if not changed it's "scalar identity behaviour" + # which is zero which is ok. + spec = Signal(3) + + # back in the LDSTRM-* and RM-* files generated by sv_analysis.py + # we marked every op with an Etype: EXTRA2 or EXTRA3, and also said + # which of the 4 (or 3 for EXTRA3) sub-fields of bits 10:18 contain + # the register-extension information. extract those how + with m.Switch(self.etype): + # 2-bit index selection mode + with m.Case(SVEtype.EXTRA2): + with m.Switch(self.idx): + with m.Case(SVEXTRA.Idx0): # 1st 2 bits + comb += spec[1:3].eq(self.extra[0:2]) + with m.Case(SVEXTRA.Idx1): # 2nd 2 bits + comb += spec[1:3].eq(self.extra[2:4]) + with m.Case(SVEXTRA.Idx2): # 3rd 2 bits + comb += spec[1:3].eq(self.extra[4:6]) + with m.Case(SVEXTRA.Idx3): # 4th 2 bits + comb += spec[1:3].eq(self.extra[6:8]) + # 3-bit index selection mode + with m.Case(SVEtype.EXTRA3): + with m.Switch(self.idx): + with m.Case(SVEXTRA.Idx0): # 1st 3 bits + comb += spec.eq(self.extra[0:3]) + with m.Case(SVEXTRA.Idx1): # 2nd 3 bits + comb += spec.eq(self.extra[3:6]) + with m.Case(SVEXTRA.Idx2): # 3rd 3 bits + comb += spec.eq(self.extra[6:9]) + # cannot fit more than 9 bits so there is no 4th thing + + # now decode it. bit 2 is "scalar/vector". note that spec could be zero + # from above, which (by design) has the effect of "no change", below. + + # simple: isvec is top bit of spec + comb += self.isvec.eq(spec[2]) + + # decode vector differently from scalar + with m.If(self.isvec): + # Vector: shifted up, extra in LSBs (RA << 2) | spec[0:1] + comb += self.reg_out.eq(Cat(spec[:2], self.reg_in)) + with m.Else(): + # Scalar: not shifted up, extra in MSBs RA | (spec[0:1] << 5) + comb += self.reg_out.eq(Cat(self.reg_in, spec[:2])) + + return m + + class DecodeA(Elaboratable): """DecodeA from instruction @@ -90,13 +162,19 @@ class DecodeA(Elaboratable): self.sel_in = Signal(In1Sel, reset_less=True) self.insn_in = Signal(32, reset_less=True) self.reg_out = Data(7, name="reg_a") + self.reg_isvec = Signal(1, name="reg_a_isvec") # TODO: in reg_out self.spr_out = Data(SPR, "spr_a") self.fast_out = Data(3, "fast_a") def elaborate(self, platform): m = Module() comb = m.d.comb + op = self.dec.op m.submodules.sprmap = sprmap = SPRMap() + m.submodules.svdec = svdec = SVP64RegExtra() + + # get the 5-bit reg data before svp64-munging it into 7-bit plus isvec + reg = Signal(5, reset_less=True) # select Register A field ra = Signal(5, reset_less=True) @@ -104,16 +182,32 @@ class DecodeA(Elaboratable): with m.If((self.sel_in == In1Sel.RA) | ((self.sel_in == In1Sel.RA_OR_ZERO) & (ra != Const(0, 5)))): - comb += self.reg_out.data.eq(ra) + comb += reg.eq(ra) comb += self.reg_out.ok.eq(1) # some Logic/ALU ops have RS as the 3rd arg, but no "RA". + # moved it to 1st position (in1_sel)... because + rs = Signal(5, reset_less=True) + comb += rs.eq(self.dec.RS) with m.If(self.sel_in == In1Sel.RS): - comb += self.reg_out.data.eq(self.dec.RS) + comb += reg.eq(rs) comb += self.reg_out.ok.eq(1) + # now do the SVP64 munging. op.SV_Etype and op.sv_in1 comes from + # PowerDecoder which in turn comes from LDST-RM*.csv and RM-*.csv + # which in turn were auto-generated by sv_analysis.py + + extra = self.sv_rm.extra # SVP64 extra bits 10:18 + comb += svdec.extra.eq(extra) # EXTRA field of SVP64 RM + comb += svdec.etype.eq(op.SV_Etype) # EXTRA2/3 for this insn + comb += svdec.idx.eq(op.sv_in1) # SVP64 reg #1 (matches in1_sel) + comb += svdec.reg_in.eq(reg) # 5-bit (RA, RS) + + # outputs: 7-bit reg number and whether it's vectorised + comb += self.reg_out.data.eq(svdec.reg_out) + comb += self.reg_isvec.eq(svdec.isvec) + # decode Fast-SPR based on instruction type - op = self.dec.op with m.Switch(op.internal_op): # BC or BCREG: implicit register (CTR) NOTE: same in DecodeOut @@ -833,11 +927,17 @@ class PowerDecode2(PowerDecodeSubset): def get_col_subset(self, opkls): subset = super().get_col_subset(opkls) - subset.add("in1_sel") subset.add("asmcode") + subset.add("in1_sel") subset.add("in2_sel") subset.add("in3_sel") subset.add("out_sel") + subset.add("sv_in1") + subset.add("sv_in2") + subset.add("sv_in3") + subset.add("sv_out") + subset.add("SV_Etype") + subset.add("SV_Ptype") subset.add("lk") subset.add("internal_op") subset.add("form")