add FP ops mftx, mxtf, mtfsr, mffsr

rocket/src/main/scala/cpu.scala

@@ -119,6 +119,8 @@ class rocketProc extends Component
     dpath.io.fpu <> fpu.io.dpath
     ctrl.io.fpu <> fpu.io.ctrl
   }
+  else
+    ctrl.io.fpu.dec.valid := Bool(false)
 
   ctrl.io.ext_mem.req_val := Bool(false)
   dpath.io.ext_mem.req_val := Bool(false)

rocket/src/main/scala/ctrl.scala

@@ -209,10 +209,12 @@ class rocketCtrl extends Component
     RDCYCLE->   List(Y,    N,BR_N,  REN_N,REN_N,A2_X,    DW_XPR,FN_X,   M_N,M_X,      MT_X, N,MUL_X,  N,DIV_X, WEN_Y,WA_RD,WB_TSC,REN_N,WEN_N,I_X ,SYNC_N,N,N,N,N),
     RDINSTRET-> List(Y,    N,BR_N,  REN_N,REN_N,A2_X,    DW_XPR,FN_X,   M_N,M_X,      MT_X, N,MUL_X,  N,DIV_X, WEN_Y,WA_RD,WB_IRT,REN_N,WEN_N,I_X ,SYNC_N,N,N,N,N),
     
-    // Instructions that have not yet been implemented
+    MFTX_S->    List(FPU_Y,N,BR_N,  REN_N,REN_N,A2_X,    DW_X,  FN_X,   M_N,M_X,      MT_X, N,MUL_X,  N,DIV_X, WEN_Y,WA_X, WB_X,  REN_N,WEN_N,I_X ,SYNC_N,N,N,N,N),
-    // Faking these for now so akaros will boot    
+    MFTX_D->    List(FPU_Y,N,BR_N,  REN_N,REN_N,A2_X,    DW_X,  FN_X,   M_N,M_X,      MT_X, N,MUL_X,  N,DIV_X, WEN_Y,WA_X, WB_X,  REN_N,WEN_N,I_X ,SYNC_N,N,N,N,N),
-    MFFSR->     List(FPU_Y,N,BR_N,  REN_N,REN_N,A2_X,    DW_X,  FN_X,   M_N,M_X,      MT_X, N,MUL_X,  N,DIV_X, WEN_N,WA_X, WB_X,  REN_N,WEN_N,I_X ,SYNC_N,N,N,N,N),
+    MXTF_S->    List(FPU_Y,N,BR_N,  REN_N,REN_Y,A2_X,    DW_X,  FN_X,   M_N,M_X,      MT_X, N,MUL_X,  N,DIV_X, WEN_N,WA_X, WB_X,  REN_N,WEN_N,I_X ,SYNC_N,N,N,N,N),
-    MTFSR->     List(FPU_Y,N,BR_N,  REN_N,REN_N,A2_X,    DW_X,  FN_X,   M_N,M_X,      MT_X, N,MUL_X,  N,DIV_X, WEN_N,WA_X, WB_X,  REN_N,WEN_N,I_X ,SYNC_N,N,N,N,Y),
+    MXTF_D->    List(FPU_Y,N,BR_N,  REN_N,REN_Y,A2_X,    DW_X,  FN_X,   M_N,M_X,      MT_X, N,MUL_X,  N,DIV_X, WEN_N,WA_X, WB_X,  REN_N,WEN_N,I_X ,SYNC_N,N,N,N,N),
+    MFFSR->     List(FPU_Y,N,BR_N,  REN_N,REN_N,A2_X,    DW_X,  FN_X,   M_N,M_X,      MT_X, N,MUL_X,  N,DIV_X, WEN_Y,WA_X, WB_X,  REN_N,WEN_N,I_X ,SYNC_N,N,N,N,N),
+    MTFSR->     List(FPU_Y,N,BR_N,  REN_N,REN_Y,A2_X,    DW_X,  FN_X,   M_N,M_X,      MT_X, N,MUL_X,  N,DIV_X, WEN_Y,WA_X, WB_X,  REN_N,WEN_N,I_X ,SYNC_N,N,N,N,N),
     FLW->       List(FPU_Y,N,BR_N,  REN_N,REN_Y,A2_ITYPE,DW_XPR,FN_ADD, M_Y,M_XRD,    MT_W, N,MUL_X,  N,DIV_X, WEN_N,WA_X, WB_ALU,REN_N,WEN_N,I_X ,SYNC_N,N,N,N,N),
     FLD->       List(FPU_Y,N,BR_N,  REN_N,REN_Y,A2_ITYPE,DW_XPR,FN_ADD, M_Y,M_XRD,    MT_D, N,MUL_X,  N,DIV_X, WEN_N,WA_X, WB_ALU,REN_N,WEN_N,I_X ,SYNC_N,N,N,N,N),
     FSW->       List(FPU_Y,N,BR_N,  REN_N,REN_Y,A2_BTYPE,DW_XPR,FN_ADD, M_Y,M_XWR,    MT_W, N,MUL_X,  N,DIV_X, WEN_N,WA_X, WB_ALU,REN_N,WEN_N,I_X ,SYNC_N,N,N,N,N),
@@ -335,6 +337,7 @@ class rocketCtrl extends Component
   val wb_reg_exception       = Reg(resetVal = Bool(false));
   val wb_reg_replay          = Reg(resetVal = Bool(false));
   val wb_reg_cause           = Reg(){UFix()};
+  val wb_reg_fp_val          = Reg(resetVal = Bool(false));
 
   val take_pc = Wire() { Bool() };
 
@@ -479,6 +482,7 @@ class rocketCtrl extends Component
     wb_reg_inst_ei     := Bool(false);
     wb_reg_flush_inst  := Bool(false);
     wb_reg_div_mul_val := Bool(false);
+    wb_reg_fp_val      := Bool(false)
   }
   .otherwise {
     wb_reg_wen         := mem_reg_wen;
@@ -488,6 +492,7 @@ class rocketCtrl extends Component
     wb_reg_inst_ei     := mem_reg_inst_ei;
     wb_reg_flush_inst  := mem_reg_flush_inst;
     wb_reg_div_mul_val := mem_reg_div_mul_val;
+    wb_reg_fp_val      := mem_reg_fp_val
   }
 
   val sboard = new rocketCtrlSboard(); 
@@ -592,7 +597,7 @@ class rocketCtrl extends Component
                      ex_reg_replay || ex_reg_mem_val && !(io.dmem.req_rdy && io.dtlb_rdy) ||
                      ex_reg_div_val && !io.dpath.div_rdy ||
                      ex_reg_mul_val && !io.dpath.mul_rdy ||
-                     io.fpu.nack
+                     ex_reg_fp_val && io.fpu.nack
   val kill_ex      = take_pc_wb || replay_ex
 
   mem_reg_replay := replay_ex && !take_pc_wb;
@@ -634,8 +639,8 @@ class rocketCtrl extends Component
      io.fpu.dec.ren2 && id_raddr2 === io.dpath.ex_waddr ||
      io.fpu.dec.ren3 && id_raddr3 === io.dpath.ex_waddr ||
      io.fpu.dec.wen  && id_waddr  === io.dpath.ex_waddr)
-  val id_ex_hazard = data_hazard_ex && (ex_reg_mem_val || ex_reg_div_val || ex_reg_mul_val) ||
+  val id_ex_hazard = data_hazard_ex && (ex_reg_mem_val || ex_reg_div_val || ex_reg_mul_val || ex_reg_fp_val) ||
-                     fp_data_hazard_ex && ex_reg_mem_val
+                     fp_data_hazard_ex && (ex_reg_mem_val || ex_reg_fp_val)
     
   // stall for RAW/WAW hazards on LB/LH and mul/div in memory stage.
   val mem_mem_cmd_bh = 
@@ -650,7 +655,8 @@ class rocketCtrl extends Component
      io.fpu.dec.ren2 && id_raddr2 === io.dpath.mem_waddr ||
      io.fpu.dec.ren3 && id_raddr3 === io.dpath.mem_waddr ||
      io.fpu.dec.wen  && id_waddr  === io.dpath.mem_waddr)
-  val id_mem_hazard = data_hazard_mem && (mem_reg_mem_val && mem_mem_cmd_bh || mem_reg_div_mul_val)
+  val id_mem_hazard = data_hazard_mem && (mem_reg_mem_val && mem_mem_cmd_bh || mem_reg_div_mul_val || mem_reg_fp_val) ||
+                      fp_data_hazard_mem && mem_reg_fp_val
   id_load_use := mem_reg_mem_val && (data_hazard_mem || fp_data_hazard_mem)
 
   // stall for RAW/WAW hazards on load/AMO misses and mul/div in writeback.
@@ -664,7 +670,7 @@ class rocketCtrl extends Component
      io.fpu.dec.ren3 && id_raddr3 === io.dpath.wb_waddr ||
      io.fpu.dec.wen  && id_waddr  === io.dpath.wb_waddr)
   val id_wb_hazard = data_hazard_wb && (wb_reg_dcache_miss || wb_reg_div_mul_val) ||
-                     fp_data_hazard_wb && wb_reg_dcache_miss
+                     fp_data_hazard_wb && (wb_reg_dcache_miss || wb_reg_fp_val)
 
   val ctrl_stalld =
     !take_pc &&

rocket/src/main/scala/dpath.scala

@@ -293,6 +293,8 @@ class rocketDpath extends Component
   mul.io.in0		 := ex_reg_rs1;
   mul.io.in1		 := ex_reg_rs2;
 
+  io.fpu.fromint_data := ex_reg_rs1
+ 
   io.ctrl.mul_rdy        := mul.io.mul_rdy
   io.ctrl.mul_result_val := mul.io.result_val;
   mul.io.result_rdy      := !dmem_resp_replay && !div.io.result_val
@@ -302,7 +304,7 @@ class rocketDpath extends Component
   // D$ request interface (registered inside D$ module)
   // other signals (req_val, req_rdy) connect to control module  
   io.dmem.req_addr  := ex_effective_address.toUFix;
-  io.dmem.req_data := (if (HAVE_FPU) Mux(io.ctrl.mem_fp_val, io.fpu.store_data, mem_reg_rs2) else mem_reg_rs2)
+  io.dmem.req_data := Mux(io.ctrl.mem_fp_val, io.fpu.store_data, mem_reg_rs2)
   io.dmem.req_tag := Cat(ex_reg_waddr, io.ctrl.ex_fp_val, io.ctrl.ex_ext_mem_val).toUFix
 
 	// processor control regfile read
@@ -392,7 +394,8 @@ class rocketDpath extends Component
                          mem_reg_waddr)))
   val mem_ll_wdata = Mux(div_result_val, div_result,
                      Mux(mul_result_val, mul_result,
-                         mem_reg_wdata))
+                     Mux(io.ctrl.mem_fp_val && io.ctrl.mem_wen, io.fpu.toint_data,
+                         mem_reg_wdata)))
   val mem_ll_wb = dmem_resp_replay || div_result_val || mul_result_val
 
   io.fpu.dmem_resp_val := io.dmem.resp_val && dmem_resp_fpu

rocket/src/main/scala/fpu.scala

@@ -7,40 +7,41 @@ import Instructions._
 
 object rocketFPConstants
 {
-  val FCMD_ADD =       Bits("b000000")
+  val FCMD_ADD =        Bits("b000000")
-  val FCMD_SUB =       Bits("b000001")
+  val FCMD_SUB =        Bits("b000001")
-  val FCMD_MUL =       Bits("b000010")
+  val FCMD_MUL =        Bits("b000010")
-  val FCMD_DIV =       Bits("b000011")
+  val FCMD_DIV =        Bits("b000011")
-  val FCMD_SQRT =      Bits("b000100")
+  val FCMD_SQRT =       Bits("b000100")
-  val FCMD_SGNINJ =    Bits("b000101")
+  val FCMD_SGNINJ =     Bits("b000101")
-  val FCMD_SGNINJN =   Bits("b000110")
+  val FCMD_SGNINJN =    Bits("b000110")
-  val FCMD_SGNMUL =    Bits("b000111")
+  val FCMD_SGNMUL =     Bits("b000111")
-  val FCMD_TRUNC_L =   Bits("b001000")
+  val FCMD_CVT_L_FMT =  Bits("b001000")
-  val FCMD_TRUNCU_L =  Bits("b001001")
+  val FCMD_CVT_LU_FMT = Bits("b001001")
-  val FCMD_TRUNC_W =   Bits("b001010")
+  val FCMD_CVT_W_FMT =  Bits("b001010")
-  val FCMD_TRUNCU_W =  Bits("b001011")
+  val FCMD_CVT_WU_FMT = Bits("b001011")
-  val FCMD_CVT_L =     Bits("b001100")
+  val FCMD_CVT_FMT_L =  Bits("b001100")
-  val FCMD_CVTU_L =    Bits("b001101")
+  val FCMD_CVT_FMT_LU = Bits("b001101")
-  val FCMD_CVT_W =     Bits("b001110")
+  val FCMD_CVT_FMT_W =  Bits("b001110")
-  val FCMD_CVTU_W =    Bits("b001111")
+  val FCMD_CVT_FMT_WU = Bits("b001111")
-  val FCMD_CVT_S =     Bits("b010000")
+  val FCMD_CVT_FMT_S =  Bits("b010000")
-  val FCMD_CVT_D =     Bits("b010001")
+  val FCMD_CVT_FMT_D =  Bits("b010001")
-  val FCMD_C_EQ =      Bits("b010101")
+  val FCMD_EQ =         Bits("b010101")
-  val FCMD_C_LT =      Bits("b010110")
+  val FCMD_LT =         Bits("b010110")
-  val FCMD_C_LE =      Bits("b010111")
+  val FCMD_LE =         Bits("b010111")
-  val FCMD_MIN =       Bits("b011000")
+  val FCMD_MIN =        Bits("b011000")
-  val FCMD_MAX =       Bits("b011001")
+  val FCMD_MAX =        Bits("b011001")
-  val FCMD_MF =        Bits("b011100")
+  val FCMD_MFTX =       Bits("b011100")
-  val FCMD_MFFSR =     Bits("b011101")
+  val FCMD_MFFSR =      Bits("b011101")
-  val FCMD_MT =        Bits("b011110")
+  val FCMD_MXTF =       Bits("b011110")
-  val FCMD_MTFSR =     Bits("b011111")
+  val FCMD_MTFSR =      Bits("b011111")
-  val FCMD_MADD =      Bits("b100100")
+  val FCMD_MADD =       Bits("b100100")
-  val FCMD_MSUB =      Bits("b100101")
+  val FCMD_MSUB =       Bits("b100101")
-  val FCMD_NMSUB =     Bits("b100110")
+  val FCMD_NMSUB =      Bits("b100110")
-  val FCMD_NMADD =     Bits("b100111")
+  val FCMD_NMADD =      Bits("b100111")
-  val FCMD_LOAD =      Bits("b111000")
+  val FCMD_LOAD =       Bits("b111000")
-  val FCMD_STORE =     Bits("b111001")
+  val FCMD_STORE =      Bits("b111001")
-  val FCMD_WIDTH =     6
+  val FCMD_WIDTH = 6
+  val FSR_WIDTH = 8
 }
 import rocketFPConstants._
 
@@ -145,8 +146,12 @@ class rocketFPUDecoder extends Component
           FLD      -> List(Y,FCMD_LOAD,    Y,N,N,N,N,N,N,N,N),
           FSW      -> List(Y,FCMD_STORE,   N,N,Y,N,Y,N,N,Y,N),
           FSD      -> List(Y,FCMD_STORE,   N,N,Y,N,N,N,N,Y,N),
-          MTFSR    -> List(Y,FCMD_MTFSR,   N,N,N,N,X,N,Y,N,Y),
+          MXTF_S   -> List(Y,FCMD_MXTF,    Y,N,N,N,Y,Y,N,N,N),
-          MFFSR    -> List(Y,FCMD_MFFSR,   N,N,N,N,X,N,Y,N,Y)
+          MXTF_D   -> List(Y,FCMD_MXTF,    Y,N,N,N,N,Y,N,N,N),
+          MFTX_S   -> List(Y,FCMD_MFTX,    N,Y,N,N,Y,N,Y,N,N),
+          MFTX_D   -> List(Y,FCMD_MFTX,    N,Y,N,N,N,N,Y,N,N),
+          MTFSR    -> List(Y,FCMD_MTFSR,   N,N,N,N,Y,Y,Y,N,Y),
+          MFFSR    -> List(Y,FCMD_MFFSR,   N,N,N,N,Y,N,Y,N,Y)
           ))
   val valid :: cmd :: wen :: ren1 :: ren2 :: ren3 :: single :: fromint :: toint :: store :: fsr :: Nil = decoder
 
@@ -165,8 +170,10 @@ class rocketFPUDecoder extends Component
 
 class ioDpathFPU extends Bundle {
   val inst = Bits(32, OUTPUT)
+  val fromint_data = Bits(64, OUTPUT)
 
   val store_data = Bits(64, INPUT)
+  val toint_data = Bits(64, INPUT)
 
   val dmem_resp_val = Bool(OUTPUT)
   val dmem_resp_tag = UFix(5, OUTPUT)
@@ -186,17 +193,62 @@ class rocketFPIntUnit extends Component
   val io = new Bundle {
     val single = Bool(INPUT)
     val cmd = Bits(FCMD_WIDTH, INPUT)
+    val fsr = Bits(FSR_WIDTH, INPUT)
     val in = Bits(65, INPUT)
-    val out = Bits(64, OUTPUT)
+    val store_data = Bits(64, OUTPUT)
+    val toint_data = Bits(64, OUTPUT)
+    val exc = Bits(5, OUTPUT)
   }
 
   val unrecoded_s = io.in(31,0)
   val unrecoded_d = io.in
 
-  val out_s = unrecoded_s
+  io.store_data := Mux(io.single, Cat(unrecoded_s, unrecoded_s), unrecoded_d)
-  val out_d = unrecoded_d
 
-  io.out := Mux(io.single, Cat(out_s, out_s), out_d)
+  val scmp = Bool(false)
+  val scmp_exc = Bits(0)
+
+  val s2i = UFix(0)
+  val s2i_exc = Bits(0)
+
+  val dcmp = Bool(false)
+  val dcmp_exc = Bits(0)
+
+  val d2i = UFix(0)
+  val d2i_exc = Bits(0)
+
+  // output muxing
+  val (out_s, exc_s) = (Wire() { Bits() }, Wire() { Bits() })
+  out_s := Cat(Fill(32, unrecoded_s(31)), unrecoded_s)
+  exc_s := Bits(0)
+  val (out_d, exc_d) = (Wire() { Bits() }, Wire() { Bits() })
+  out_d := unrecoded_d
+  exc_d := Bits(0)
+
+  when (io.cmd === FCMD_MTFSR || io.cmd === FCMD_MFFSR) {
+    out_s := io.fsr
+  }
+  when (io.cmd === FCMD_CVT_W_FMT || io.cmd === FCMD_CVT_WU_FMT) {
+    out_s := Cat(Fill(32, s2i(31)), s2i(31,0))
+    exc_s := s2i_exc
+    out_d := Cat(Fill(32, d2i(31)), d2i(31,0))
+    exc_d := d2i_exc
+  }
+  when (io.cmd === FCMD_CVT_L_FMT || io.cmd === FCMD_CVT_LU_FMT) {
+    out_s := s2i
+    exc_s := s2i_exc
+    out_d := d2i
+    exc_d := d2i_exc
+  }
+  when (io.cmd === FCMD_EQ || io.cmd === FCMD_LT || io.cmd === FCMD_LE) {
+    out_s := scmp
+    exc_s := scmp_exc
+    out_d := dcmp
+    exc_d := dcmp_exc
+  }
+
+  io.toint_data := Mux(io.single, out_s, out_d)
+  io.exc := Mux(io.single, exc_s, exc_d)
 }
 
 class rocketFPU extends Component
@@ -229,21 +281,36 @@ class rocketFPU extends Component
     load_wb_tag := io.dpath.dmem_resp_tag
   }
 
+  val fsr_rm = Reg() { Bits(width = 3) }
+  val fsr_exc = Reg() { Bits(width = 5) }
+
   // regfile
   val regfile = Mem(32, load_wb, load_wb_tag, load_wb_data);
   regfile.setReadLatency(0);
   regfile.setTarget('inst);
 
-  val ex_rs1 = regfile.read(reg_inst(16,12))
+  val ex_rs1 = regfile.read(reg_inst(26,22))
   val ex_rs2 = regfile.read(reg_inst(21,17))
-  val ex_rs3 = regfile.read(reg_inst(26,22))
+  val ex_rs3 = regfile.read(reg_inst(16,12))
 
+  val fp_fromint_val = Reg(resetVal = Bool(false))
+  val fp_fromint_data = Reg() { Bits() }
+  val fp_toint_val = Reg(resetVal = Bool(false))
   val fp_toint_data = Reg() { Bits() }
   val fp_toint_single = Reg() { Bool() }
   val fp_toint_cmd = Reg() { Bits() }
+  val fp_waddr = Reg() { Bits() }
 
-  when (reg_valid) {
+  fp_fromint_val := Bool(false)
+  fp_toint_val := Bool(false)
+  when (reg_valid && !io.ctrl.killx) {
+    fp_waddr := reg_inst(31,27)
+    when (ctrl.fromint) {
+      fp_fromint_val := Bool(true)
+      fp_fromint_data := io.dpath.fromint_data
+    }
     when (ctrl.toint) {
+      fp_toint_val := Bool(true)
       fp_toint_data := ex_rs1
     }
     when (ctrl.store) {
@@ -259,12 +326,33 @@ class rocketFPU extends Component
   val fpiu = new rocketFPIntUnit
   fpiu.io.single := ctrl.single
   fpiu.io.cmd := ctrl.cmd
+  fpiu.io.fsr := Cat(fsr_rm, fsr_exc)
   fpiu.io.in := fp_toint_data
 
-  io.dpath.store_data := fpiu.io.out
+  io.dpath.store_data := fpiu.io.store_data
+  io.dpath.toint_data := fpiu.io.toint_data
 
-  val fsr_busy = ctrl.fsr && Bool(false)
+  val retire_toint = Reg(!io.ctrl.killm && fp_toint_val, resetVal = Bool(false))
+  val retire_toint_exc = Reg(fpiu.io.exc)
+  val retire_fromint = Reg(!io.ctrl.killm && fp_fromint_val, resetVal = Bool(false))
+  val retire_fromint_wdata = Reg(fp_fromint_data)
+  val retire_fromint_waddr = Reg(fp_waddr)
+
+  when (retire_toint) {
+    fsr_exc := fsr_exc | retire_toint_exc
+  }
+  when (retire_toint && retire_fromint) { // MTFSR
+    fsr_exc := retire_fromint_wdata(4,0)
+    fsr_rm := retire_fromint_wdata(7,5)
+  }
+
+  regfile.write(retire_fromint_waddr, retire_fromint_wdata, retire_fromint && !retire_toint)
+
+  val fp_inflight = fp_toint_val || retire_toint || fp_fromint_val || retire_fromint
+  val mtfsr_inflight = fp_toint_val && fp_fromint_val || retire_toint && retire_fromint
+  val fsr_busy = ctrl.fsr && fp_inflight || mtfsr_inflight
   val units_busy = Bool(false)
-  io.ctrl.nack := reg_valid && (fsr_busy || units_busy)
+  val write_port_busy = Bool(false)
+  io.ctrl.nack := fsr_busy || units_busy || write_port_busy
   io.ctrl.dec <> fp_decoder.io.sigs
 }