riscv/rocket-chip
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add FP ops mftx, mxtf, mtfsr, mffsr

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This commit is contained in:
Andrew Waterman 2012-02-12 20:12:53 -08:00
parent 9bb1558a34
commit 08b6517a23
4 changed files with 156 additions and 57 deletions
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2
rocket/src/main/scala/cpu.scala
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@ -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)

24
rocket/src/main/scala/ctrl.scala
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@ -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
// Faking these for now so akaros will boot
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),
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),
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),
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),
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),
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) ||
fp_data_hazard_ex && ex_reg_mem_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 || 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 &&

7
rocket/src/main/scala/dpath.scala
View File

@ -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

180
rocket/src/main/scala/fpu.scala
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@ -7,40 +7,41 @@ import Instructions._
object rocketFPConstants
{
val FCMD_ADD = Bits("b000000")
val FCMD_SUB = Bits("b000001")
val FCMD_MUL = Bits("b000010")
val FCMD_DIV = Bits("b000011")
val FCMD_SQRT = Bits("b000100")
val FCMD_SGNINJ = Bits("b000101")
val FCMD_SGNINJN = Bits("b000110")
val FCMD_SGNMUL = Bits("b000111")
val FCMD_TRUNC_L = Bits("b001000")
val FCMD_TRUNCU_L = Bits("b001001")
val FCMD_TRUNC_W = Bits("b001010")
val FCMD_TRUNCU_W = Bits("b001011")
val FCMD_CVT_L = Bits("b001100")
val FCMD_CVTU_L = Bits("b001101")
val FCMD_CVT_W = Bits("b001110")
val FCMD_CVTU_W = Bits("b001111")
val FCMD_CVT_S = Bits("b010000")
val FCMD_CVT_D = Bits("b010001")
val FCMD_C_EQ = Bits("b010101")
val FCMD_C_LT = Bits("b010110")
val FCMD_C_LE = Bits("b010111")
val FCMD_MIN = Bits("b011000")
val FCMD_MAX = Bits("b011001")
val FCMD_MF = Bits("b011100")
val FCMD_MFFSR = Bits("b011101")
val FCMD_MT = Bits("b011110")
val FCMD_MTFSR = Bits("b011111")
val FCMD_MADD = Bits("b100100")
val FCMD_MSUB = Bits("b100101")
val FCMD_NMSUB = Bits("b100110")
val FCMD_NMADD = Bits("b100111")
val FCMD_LOAD = Bits("b111000")
val FCMD_STORE = Bits("b111001")
val FCMD_WIDTH = 6
val FCMD_ADD = Bits("b000000")
val FCMD_SUB = Bits("b000001")
val FCMD_MUL = Bits("b000010")
val FCMD_DIV = Bits("b000011")
val FCMD_SQRT = Bits("b000100")
val FCMD_SGNINJ = Bits("b000101")
val FCMD_SGNINJN = Bits("b000110")
val FCMD_SGNMUL = Bits("b000111")
val FCMD_CVT_L_FMT = Bits("b001000")
val FCMD_CVT_LU_FMT = Bits("b001001")
val FCMD_CVT_W_FMT = Bits("b001010")
val FCMD_CVT_WU_FMT = Bits("b001011")
val FCMD_CVT_FMT_L = Bits("b001100")
val FCMD_CVT_FMT_LU = Bits("b001101")
val FCMD_CVT_FMT_W = Bits("b001110")
val FCMD_CVT_FMT_WU = Bits("b001111")
val FCMD_CVT_FMT_S = Bits("b010000")
val FCMD_CVT_FMT_D = Bits("b010001")
val FCMD_EQ = Bits("b010101")
val FCMD_LT = Bits("b010110")
val FCMD_LE = Bits("b010111")
val FCMD_MIN = Bits("b011000")
val FCMD_MAX = Bits("b011001")
val FCMD_MFTX = Bits("b011100")
val FCMD_MFFSR = Bits("b011101")
val FCMD_MXTF = Bits("b011110")
val FCMD_MTFSR = Bits("b011111")
val FCMD_MADD = Bits("b100100")
val FCMD_MSUB = Bits("b100101")
val FCMD_NMSUB = Bits("b100110")
val FCMD_NMADD = Bits("b100111")
val FCMD_LOAD = Bits("b111000")
val FCMD_STORE = Bits("b111001")
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),
MFFSR -> List(Y,FCMD_MFFSR, N,N,N,N,X,N,Y,N,Y)
MXTF_S -> List(Y,FCMD_MXTF, Y,N,N,N,Y,Y,N,N,N),
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
val out_d = unrecoded_d
io.store_data := Mux(io.single, Cat(unrecoded_s, unrecoded_s), 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
}