riscv/rocket-chip
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improved instruction decoding

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it now makes use of don't-cares by performing logic minimization
This commit is contained in:
Andrew Waterman
2012-05-01 20:16:36 -07:00
parent 4cfa6cd9a8
commit 65ff397122
5 changed files with 506 additions and 308 deletions
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124
rocket/src/main/scala/fpu.scala
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@ -40,6 +40,7 @@ object rocketFPConstants
val FCMD_NMADD = Bits("b100111")
val FCMD_LOAD = Bits("b111000")
val FCMD_STORE = Bits("b111001")
val FCMD_X = Bits("b??????")
val FCMD_WIDTH = 6
val FSR_WIDTH = 8
}
@ -48,7 +49,6 @@ import rocketFPConstants._
class rocketFPUCtrlSigs extends Bundle
{
val cmd = Bits(width = FCMD_WIDTH)
val valid = Bool()
val wen = Bool()
val sboard = Bool()
val ren1 = Bool()
@ -74,71 +74,69 @@ class rocketFPUDecoder extends Component
val N = Bool(false)
val Y = Bool(true)
val X = Bool(false)
val FCMD_X = FCMD_ADD
val decoder = ListLookup(io.inst,
List (N,FCMD_X, X,X,X,X,X,X,X,X,X,X,X,X,X),
Array(FLW -> List(Y,FCMD_LOAD, Y,N,N,N,N,Y,N,N,N,N,N,N,N),
FLD -> List(Y,FCMD_LOAD, Y,N,N,N,N,N,N,N,N,N,N,N,N),
FSW -> List(Y,FCMD_STORE, N,N,N,Y,N,Y,N,N,N,N,Y,N,N),
FSD -> List(Y,FCMD_STORE, N,N,N,Y,N,N,N,N,N,N,Y,N,N),
MXTF_S -> List(Y,FCMD_MXTF, Y,N,N,N,N,Y,Y,N,Y,N,N,N,N),
MXTF_D -> List(Y,FCMD_MXTF, Y,N,N,N,N,N,Y,N,Y,N,N,N,N),
FCVT_S_W -> List(Y,FCMD_CVT_FMT_W, Y,N,N,N,N,Y,Y,N,Y,N,N,N,N),
FCVT_S_WU-> List(Y,FCMD_CVT_FMT_WU,Y,N,N,N,N,Y,Y,N,Y,N,N,N,N),
FCVT_S_L -> List(Y,FCMD_CVT_FMT_L, Y,N,N,N,N,Y,Y,N,Y,N,N,N,N),
FCVT_S_LU-> List(Y,FCMD_CVT_FMT_LU,Y,N,N,N,N,Y,Y,N,Y,N,N,N,N),
FCVT_D_W -> List(Y,FCMD_CVT_FMT_W, Y,N,N,N,N,N,Y,N,Y,N,N,N,N),
FCVT_D_WU-> List(Y,FCMD_CVT_FMT_WU,Y,N,N,N,N,N,Y,N,Y,N,N,N,N),
FCVT_D_L -> List(Y,FCMD_CVT_FMT_L, Y,N,N,N,N,N,Y,N,Y,N,N,N,N),
FCVT_D_LU-> List(Y,FCMD_CVT_FMT_LU,Y,N,N,N,N,N,Y,N,Y,N,N,N,N),
MFTX_S -> List(Y,FCMD_MFTX, N,N,Y,N,N,Y,N,Y,N,N,N,N,N),
MFTX_D -> List(Y,FCMD_MFTX, N,N,Y,N,N,N,N,Y,N,N,N,N,N),
FCVT_W_S -> List(Y,FCMD_CVT_W_FMT, N,N,Y,N,N,Y,N,Y,N,N,N,N,N),
FCVT_WU_S-> List(Y,FCMD_CVT_WU_FMT,N,N,Y,N,N,Y,N,Y,N,N,N,N,N),
FCVT_L_S -> List(Y,FCMD_CVT_L_FMT, N,N,Y,N,N,Y,N,Y,N,N,N,N,N),
FCVT_LU_S-> List(Y,FCMD_CVT_LU_FMT,N,N,Y,N,N,Y,N,Y,N,N,N,N,N),
FCVT_W_D -> List(Y,FCMD_CVT_W_FMT, N,N,Y,N,N,N,N,Y,N,N,N,N,N),
FCVT_WU_D-> List(Y,FCMD_CVT_WU_FMT,N,N,Y,N,N,N,N,Y,N,N,N,N,N),
FCVT_L_D -> List(Y,FCMD_CVT_L_FMT, N,N,Y,N,N,N,N,Y,N,N,N,N,N),
FCVT_LU_D-> List(Y,FCMD_CVT_LU_FMT,N,N,Y,N,N,N,N,Y,N,N,N,N,N),
FCVT_S_D -> List(Y,FCMD_CVT_FMT_D, Y,N,Y,N,N,Y,N,N,Y,N,N,N,N),
FCVT_D_S -> List(Y,FCMD_CVT_FMT_S, Y,N,Y,N,N,N,N,N,Y,N,N,N,N),
FEQ_S -> List(Y,FCMD_EQ, N,N,Y,Y,N,Y,N,Y,N,N,N,N,N),
FLT_S -> List(Y,FCMD_LT, N,N,Y,Y,N,Y,N,Y,N,N,N,N,N),
FLE_S -> List(Y,FCMD_LE, N,N,Y,Y,N,Y,N,Y,N,N,N,N,N),
FEQ_D -> List(Y,FCMD_EQ, N,N,Y,Y,N,N,N,Y,N,N,N,N,N),
FLT_D -> List(Y,FCMD_LT, N,N,Y,Y,N,N,N,Y,N,N,N,N,N),
FLE_D -> List(Y,FCMD_LE, N,N,Y,Y,N,N,N,Y,N,N,N,N,N),
MTFSR -> List(Y,FCMD_MTFSR, N,N,N,N,N,Y,N,Y,N,N,N,Y,Y),
MFFSR -> List(Y,FCMD_MFFSR, N,N,N,N,N,Y,N,Y,N,N,N,Y,N),
FSGNJ_S -> List(Y,FCMD_SGNJ, Y,N,Y,Y,N,Y,N,N,Y,N,N,N,N),
FSGNJN_S -> List(Y,FCMD_SGNJN, Y,N,Y,Y,N,Y,N,N,Y,N,N,N,N),
FSGNJX_S -> List(Y,FCMD_SGNJX, Y,N,Y,Y,N,Y,N,N,Y,N,N,N,N),
FSGNJ_D -> List(Y,FCMD_SGNJ, Y,N,Y,Y,N,N,N,N,Y,N,N,N,N),
FSGNJN_D -> List(Y,FCMD_SGNJN, Y,N,Y,Y,N,N,N,N,Y,N,N,N,N),
FSGNJX_D -> List(Y,FCMD_SGNJX, Y,N,Y,Y,N,N,N,N,Y,N,N,N,N),
FMIN_S -> List(Y,FCMD_MIN, Y,N,Y,Y,N,Y,N,N,Y,N,N,N,N),
FMAX_S -> List(Y,FCMD_MAX, Y,N,Y,Y,N,Y,N,N,Y,N,N,N,N),
FMIN_D -> List(Y,FCMD_MIN, Y,N,Y,Y,N,N,N,N,Y,N,N,N,N),
FMAX_D -> List(Y,FCMD_MAX, Y,N,Y,Y,N,N,N,N,Y,N,N,N,N),
FADD_S -> List(Y,FCMD_ADD, Y,Y,Y,Y,N,Y,N,N,N,Y,N,N,N),
FSUB_S -> List(Y,FCMD_SUB, Y,Y,Y,Y,N,Y,N,N,N,Y,N,N,N),
FMUL_S -> List(Y,FCMD_MUL, Y,Y,Y,Y,N,Y,N,N,N,Y,N,N,N),
FADD_D -> List(Y,FCMD_ADD, Y,Y,Y,Y,N,N,N,N,N,Y,N,N,N),
FSUB_D -> List(Y,FCMD_SUB, Y,Y,Y,Y,N,N,N,N,N,Y,N,N,N),
FMUL_D -> List(Y,FCMD_MUL, Y,Y,Y,Y,N,N,N,N,N,Y,N,N,N),
FMADD_S -> List(Y,FCMD_MADD, Y,Y,Y,Y,Y,Y,N,N,N,Y,N,N,N),
FMSUB_S -> List(Y,FCMD_MSUB, Y,Y,Y,Y,Y,Y,N,N,N,Y,N,N,N),
FNMADD_S -> List(Y,FCMD_NMADD, Y,Y,Y,Y,Y,Y,N,N,N,Y,N,N,N),
FNMSUB_S -> List(Y,FCMD_NMSUB, Y,Y,Y,Y,Y,Y,N,N,N,Y,N,N,N),
FMADD_D -> List(Y,FCMD_MADD, Y,Y,Y,Y,Y,N,N,N,N,Y,N,N,N),
FMSUB_D -> List(Y,FCMD_MSUB, Y,Y,Y,Y,Y,N,N,N,N,Y,N,N,N),
FNMADD_D -> List(Y,FCMD_NMADD, Y,Y,Y,Y,Y,N,N,N,N,Y,N,N,N),
FNMSUB_D -> List(Y,FCMD_NMSUB, Y,Y,Y,Y,Y,N,N,N,N,Y,N,N,N)
List (FCMD_X, X,X,X,X,X,X,X,X,X,X,X,X,X),
Array(FLW -> List(FCMD_LOAD, Y,N,N,N,N,Y,N,N,N,N,N,N,N),
FLD -> List(FCMD_LOAD, Y,N,N,N,N,N,N,N,N,N,N,N,N),
FSW -> List(FCMD_STORE, N,N,N,Y,N,Y,N,N,N,N,Y,N,N),
FSD -> List(FCMD_STORE, N,N,N,Y,N,N,N,N,N,N,Y,N,N),
MXTF_S -> List(FCMD_MXTF, Y,N,N,N,N,Y,Y,N,Y,N,N,N,N),
MXTF_D -> List(FCMD_MXTF, Y,N,N,N,N,N,Y,N,Y,N,N,N,N),
FCVT_S_W -> List(FCMD_CVT_FMT_W, Y,N,N,N,N,Y,Y,N,Y,N,N,N,N),
FCVT_S_WU-> List(FCMD_CVT_FMT_WU,Y,N,N,N,N,Y,Y,N,Y,N,N,N,N),
FCVT_S_L -> List(FCMD_CVT_FMT_L, Y,N,N,N,N,Y,Y,N,Y,N,N,N,N),
FCVT_S_LU-> List(FCMD_CVT_FMT_LU,Y,N,N,N,N,Y,Y,N,Y,N,N,N,N),
FCVT_D_W -> List(FCMD_CVT_FMT_W, Y,N,N,N,N,N,Y,N,Y,N,N,N,N),
FCVT_D_WU-> List(FCMD_CVT_FMT_WU,Y,N,N,N,N,N,Y,N,Y,N,N,N,N),
FCVT_D_L -> List(FCMD_CVT_FMT_L, Y,N,N,N,N,N,Y,N,Y,N,N,N,N),
FCVT_D_LU-> List(FCMD_CVT_FMT_LU,Y,N,N,N,N,N,Y,N,Y,N,N,N,N),
MFTX_S -> List(FCMD_MFTX, N,N,Y,N,N,Y,N,Y,N,N,N,N,N),
MFTX_D -> List(FCMD_MFTX, N,N,Y,N,N,N,N,Y,N,N,N,N,N),
FCVT_W_S -> List(FCMD_CVT_W_FMT, N,N,Y,N,N,Y,N,Y,N,N,N,N,N),
FCVT_WU_S-> List(FCMD_CVT_WU_FMT,N,N,Y,N,N,Y,N,Y,N,N,N,N,N),
FCVT_L_S -> List(FCMD_CVT_L_FMT, N,N,Y,N,N,Y,N,Y,N,N,N,N,N),
FCVT_LU_S-> List(FCMD_CVT_LU_FMT,N,N,Y,N,N,Y,N,Y,N,N,N,N,N),
FCVT_W_D -> List(FCMD_CVT_W_FMT, N,N,Y,N,N,N,N,Y,N,N,N,N,N),
FCVT_WU_D-> List(FCMD_CVT_WU_FMT,N,N,Y,N,N,N,N,Y,N,N,N,N,N),
FCVT_L_D -> List(FCMD_CVT_L_FMT, N,N,Y,N,N,N,N,Y,N,N,N,N,N),
FCVT_LU_D-> List(FCMD_CVT_LU_FMT,N,N,Y,N,N,N,N,Y,N,N,N,N,N),
FCVT_S_D -> List(FCMD_CVT_FMT_D, Y,N,Y,N,N,Y,N,N,Y,N,N,N,N),
FCVT_D_S -> List(FCMD_CVT_FMT_S, Y,N,Y,N,N,N,N,N,Y,N,N,N,N),
FEQ_S -> List(FCMD_EQ, N,N,Y,Y,N,Y,N,Y,N,N,N,N,N),
FLT_S -> List(FCMD_LT, N,N,Y,Y,N,Y,N,Y,N,N,N,N,N),
FLE_S -> List(FCMD_LE, N,N,Y,Y,N,Y,N,Y,N,N,N,N,N),
FEQ_D -> List(FCMD_EQ, N,N,Y,Y,N,N,N,Y,N,N,N,N,N),
FLT_D -> List(FCMD_LT, N,N,Y,Y,N,N,N,Y,N,N,N,N,N),
FLE_D -> List(FCMD_LE, N,N,Y,Y,N,N,N,Y,N,N,N,N,N),
MTFSR -> List(FCMD_MTFSR, N,N,N,N,N,Y,N,Y,N,N,N,Y,Y),
MFFSR -> List(FCMD_MFFSR, N,N,N,N,N,Y,N,Y,N,N,N,Y,N),
FSGNJ_S -> List(FCMD_SGNJ, Y,N,Y,Y,N,Y,N,N,Y,N,N,N,N),
FSGNJN_S -> List(FCMD_SGNJN, Y,N,Y,Y,N,Y,N,N,Y,N,N,N,N),
FSGNJX_S -> List(FCMD_SGNJX, Y,N,Y,Y,N,Y,N,N,Y,N,N,N,N),
FSGNJ_D -> List(FCMD_SGNJ, Y,N,Y,Y,N,N,N,N,Y,N,N,N,N),
FSGNJN_D -> List(FCMD_SGNJN, Y,N,Y,Y,N,N,N,N,Y,N,N,N,N),
FSGNJX_D -> List(FCMD_SGNJX, Y,N,Y,Y,N,N,N,N,Y,N,N,N,N),
FMIN_S -> List(FCMD_MIN, Y,N,Y,Y,N,Y,N,N,Y,N,N,N,N),
FMAX_S -> List(FCMD_MAX, Y,N,Y,Y,N,Y,N,N,Y,N,N,N,N),
FMIN_D -> List(FCMD_MIN, Y,N,Y,Y,N,N,N,N,Y,N,N,N,N),
FMAX_D -> List(FCMD_MAX, Y,N,Y,Y,N,N,N,N,Y,N,N,N,N),
FADD_S -> List(FCMD_ADD, Y,Y,Y,Y,N,Y,N,N,N,Y,N,N,N),
FSUB_S -> List(FCMD_SUB, Y,Y,Y,Y,N,Y,N,N,N,Y,N,N,N),
FMUL_S -> List(FCMD_MUL, Y,Y,Y,Y,N,Y,N,N,N,Y,N,N,N),
FADD_D -> List(FCMD_ADD, Y,Y,Y,Y,N,N,N,N,N,Y,N,N,N),
FSUB_D -> List(FCMD_SUB, Y,Y,Y,Y,N,N,N,N,N,Y,N,N,N),
FMUL_D -> List(FCMD_MUL, Y,Y,Y,Y,N,N,N,N,N,Y,N,N,N),
FMADD_S -> List(FCMD_MADD, Y,Y,Y,Y,Y,Y,N,N,N,Y,N,N,N),
FMSUB_S -> List(FCMD_MSUB, Y,Y,Y,Y,Y,Y,N,N,N,Y,N,N,N),
FNMADD_S -> List(FCMD_NMADD, Y,Y,Y,Y,Y,Y,N,N,N,Y,N,N,N),
FNMSUB_S -> List(FCMD_NMSUB, Y,Y,Y,Y,Y,Y,N,N,N,Y,N,N,N),
FMADD_D -> List(FCMD_MADD, Y,Y,Y,Y,Y,N,N,N,N,Y,N,N,N),
FMSUB_D -> List(FCMD_MSUB, Y,Y,Y,Y,Y,N,N,N,N,Y,N,N,N),
FNMADD_D -> List(FCMD_NMADD, Y,Y,Y,Y,Y,N,N,N,N,Y,N,N,N),
FNMSUB_D -> List(FCMD_NMSUB, Y,Y,Y,Y,Y,N,N,N,N,Y,N,N,N)
))
val valid :: cmd :: wen :: sboard :: ren1 :: ren2 :: ren3 :: single :: fromint :: toint :: fastpipe :: fma :: store :: rdfsr :: wrfsr :: Nil = decoder
val cmd :: wen :: sboard :: ren1 :: ren2 :: ren3 :: single :: fromint :: toint :: fastpipe :: fma :: store :: rdfsr :: wrfsr :: Nil = decoder
io.sigs.valid := valid.toBool
io.sigs.cmd := cmd
io.sigs.wen := wen.toBool
io.sigs.sboard := sboard.toBool