riscv/rocket-chip
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expose FMA ports outside of FPU (for the VU)

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This commit is contained in:
Andrew Waterman 2012-02-23 17:39:34 -08:00
parent 6ceaa0e80a
commit 5332bab6f1
2 changed files with 67 additions and 67 deletions
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20
rocket/src/main/scala/cpu.scala
View File

@ -97,18 +97,16 @@ class rocketProc(resetSignal: Bool = null) extends Component(resetSignal)
dpath.io.dmem.resp_data := arb.io.cpu.resp_data;
dpath.io.dmem.resp_data_subword := io.dmem.resp_data_subword;
var fpu: rocketFPU = null
if (HAVE_FPU)
{
val fpu = new rocketFPU(4,6)
fpu = new rocketFPU(4,6)
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)
if (HAVE_VEC)
{
dpath.io.vec_ctrl <> ctrl.io.vec_dpath
@ -161,5 +159,19 @@ class rocketProc(resetSignal: Bool = null) extends Component(resetSignal)
vu.io.dmem_resp.bits.data := dpath.io.ext_mem.resp_data
vu.io.dmem_resp.bits.tag := dpath.io.ext_mem.resp_tag
vu.io.dmem_resp.bits.typ := dpath.io.ext_mem.resp_type
fpu.io.sfma.valid := Bool(false)
fpu.io.dfma.valid := Bool(false)
}
else
{
ctrl.io.ext_mem.req_val := Bool(false)
dpath.io.ext_mem.req_val := Bool(false)
if (HAVE_FPU)
{
fpu.io.sfma.valid := Bool(false)
fpu.io.dfma.valid := Bool(false)
}
}
}

114
rocket/src/main/scala/fpu.scala
View File

@ -365,18 +365,20 @@ class rocketFPUFastPipe extends Component
io.exc_d := exc_d
}
class ioFMA(width: Int) extends Bundle {
val valid = Bool(INPUT)
val cmd = Bits(FCMD_WIDTH, INPUT)
val rm = Bits(3, INPUT)
val in1 = Bits(width, INPUT)
val in2 = Bits(width, INPUT)
val in3 = Bits(width, INPUT)
val out = Bits(width, OUTPUT)
val exc = Bits(5, OUTPUT)
}
class rocketFPUSFMAPipe(latency: Int) extends Component
{
val io = new Bundle {
val valid = Bool(INPUT)
val cmd = Bits(FCMD_WIDTH, INPUT)
val rm = Bits(3, INPUT)
val in1 = Bits(33, INPUT)
val in2 = Bits(33, INPUT)
val in3 = Bits(33, INPUT)
val out = Bits(33, OUTPUT)
val exc = Bits(5, OUTPUT)
}
val io = new ioFMA(33)
val cmd = Reg() { Bits() }
val rm = Reg() { Bits() }
@ -409,16 +411,7 @@ class rocketFPUSFMAPipe(latency: Int) extends Component
class rocketFPUDFMAPipe(latency: Int) extends Component
{
val io = new Bundle {
val valid = Bool(INPUT)
val cmd = Bits(FCMD_WIDTH, INPUT)
val rm = Bits(3, INPUT)
val in1 = Bits(65, INPUT)
val in2 = Bits(65, INPUT)
val in3 = Bits(65, INPUT)
val out = Bits(65, OUTPUT)
val exc = Bits(5, OUTPUT)
}
val io = new ioFMA(65)
val cmd = Reg() { Bits() }
val rm = Reg() { Bits() }
@ -454,13 +447,15 @@ class rocketFPU(sfma_latency: Int, dfma_latency: Int) extends Component
val io = new Bundle {
val ctrl = new ioCtrlFPU().flip()
val dpath = new ioDpathFPU().flip()
val sfma = new ioFMA(33)
val dfma = new ioFMA(65)
}
val reg_inst = Reg() { Bits() }
val ex_reg_inst = Reg() { Bits() }
when (io.ctrl.valid) {
reg_inst := io.dpath.inst
ex_reg_inst := io.dpath.inst
}
val reg_valid = Reg(io.ctrl.valid, Bool(false))
val ex_reg_valid = Reg(io.ctrl.valid, Bool(false))
val fp_decoder = new rocketFPUDecoder
fp_decoder.io.inst := io.dpath.inst
@ -470,6 +465,7 @@ class rocketFPU(sfma_latency: Int, dfma_latency: Int) extends Component
ctrl := fp_decoder.io.sigs
}
val mem_ctrl = Reg(ctrl)
val wb_ctrl = Reg(mem_ctrl)
// load response
val load_wb = Reg(io.dpath.dmem_resp_val, resetVal = Bool(false))
@ -496,32 +492,23 @@ class rocketFPU(sfma_latency: Int, dfma_latency: Int) extends Component
regfile.setReadLatency(0);
regfile.setTarget('inst);
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(16,12))
val ex_rm = Mux(reg_inst(11,9) === Bits(7), fsr_rm, reg_inst(11,9))
val ex_rs1 = regfile.read(ex_reg_inst(26,22))
val ex_rs2 = regfile.read(ex_reg_inst(21,17))
val ex_rs3 = regfile.read(ex_reg_inst(16,12))
val ex_rm = Mux(ex_reg_inst(11,9) === Bits(7), fsr_rm, ex_reg_inst(11,9))
val mem_reg_valid = Reg(ex_reg_valid && !io.ctrl.killx, resetVal = Bool(false))
val mem_fromint_data = Reg() { Bits() }
val mem_toint_val = Reg(resetVal = Bool(false))
val mem_rs1 = Reg() { Bits() }
val mem_rs2 = Reg() { Bits() }
val mem_rs3 = Reg() { Bits() }
val mem_rm = Reg() { Bits() }
val mem_wrfsr_val = Reg(resetVal = Bool(false))
mem_toint_val := Bool(false)
mem_wrfsr_val := Bool(false)
when (reg_valid) {
when (ex_reg_valid) {
mem_rm := ex_rm
when (ctrl.fromint || ctrl.wrfsr) {
mem_fromint_data := io.dpath.fromint_data
}
when (ctrl.wrfsr) {
mem_wrfsr_val := !io.ctrl.killx
}
when (ctrl.toint) {
mem_toint_val := !io.ctrl.killx
}
when (ctrl.ren1) {
mem_rs1 := ex_rs1
}
@ -563,23 +550,26 @@ class rocketFPU(sfma_latency: Int, dfma_latency: Int) extends Component
mem_ctrl.cmd === FCMD_NMADD || mem_ctrl.cmd === FCMD_NMSUB
val cmd_addsub = mem_ctrl.cmd === FCMD_ADD || mem_ctrl.cmd === FCMD_SUB
val sfma = new rocketFPUSFMAPipe(sfma_latency-1)
sfma.io.valid := Reg(reg_valid && ctrl.fma && ctrl.single)
sfma.io.in1 := mem_rs1
sfma.io.in2 := mem_rs2
sfma.io.in3 := mem_rs3
sfma.io.cmd := mem_ctrl.cmd
sfma.io.rm := mem_rm
sfma.io.valid := io.sfma.valid || mem_reg_valid && mem_ctrl.fma && mem_ctrl.single
sfma.io.in1 := Mux(io.sfma.valid, io.sfma.in1, mem_rs1)
sfma.io.in2 := Mux(io.sfma.valid, io.sfma.in2, mem_rs2)
sfma.io.in3 := Mux(io.sfma.valid, io.sfma.in3, mem_rs3)
sfma.io.cmd := Mux(io.sfma.valid, io.sfma.cmd, mem_ctrl.cmd)
sfma.io.rm := Mux(io.sfma.valid, io.sfma.rm, mem_rm)
io.sfma.out := sfma.io.out
io.sfma.exc := sfma.io.exc
val dfma = new rocketFPUDFMAPipe(dfma_latency-1)
dfma.io.valid := Reg(reg_valid && ctrl.fma && !ctrl.single)
dfma.io.in1 := mem_rs1
dfma.io.in2 := mem_rs2
dfma.io.in3 := mem_rs3
dfma.io.cmd := mem_ctrl.cmd
dfma.io.rm := mem_rm
dfma.io.valid := io.dfma.valid || mem_reg_valid && mem_ctrl.fma && !mem_ctrl.single
dfma.io.in1 := Mux(io.dfma.valid, io.dfma.in1, mem_rs1)
dfma.io.in2 := Mux(io.dfma.valid, io.dfma.in2, mem_rs2)
dfma.io.in3 := Mux(io.dfma.valid, io.dfma.in3, mem_rs3)
dfma.io.cmd := Mux(io.dfma.valid, io.dfma.cmd, mem_ctrl.cmd)
dfma.io.rm := Mux(io.dfma.valid, io.dfma.rm, mem_rm)
io.dfma.out := dfma.io.out
io.dfma.exc := dfma.io.exc
val wb_wrfsr_val = Reg(!io.ctrl.killm && mem_wrfsr_val, resetVal = Bool(false))
val wb_toint_val = Reg(!io.ctrl.killm && mem_toint_val, resetVal = Bool(false))
val wb_reg_valid = Reg(mem_reg_valid && !io.ctrl.killm, resetVal = Bool(false))
val wb_toint_exc = Reg(fpiu.io.exc)
// writeback arbitration
@ -596,13 +586,14 @@ class rocketFPU(sfma_latency: Int, dfma_latency: Int) extends Component
val write_port_busy = ctrl.fastpipe && wen(fastpipe_latency) ||
Bool(sfma_latency < dfma_latency) && ctrl.fma && ctrl.single && wen(sfma_latency) ||
mem_wen && mem_fu_latency === ex_stage_fu_latency
mem_wen := reg_valid && !io.ctrl.killx && (ctrl.fma || ctrl.fastpipe)
mem_wen := ex_reg_valid && !io.ctrl.killx && (ctrl.fma || ctrl.fastpipe)
val ex_stage_wsrc = Cat(ctrl.fastpipe, ctrl.single)
val mem_winfo = Reg(Cat(reg_inst(31,27), ex_stage_wsrc))
val mem_winfo = Reg(Cat(ex_reg_inst(31,27), ex_stage_wsrc))
for (i <- 0 until dfma_latency-2) {
winfo(i) := winfo(i+1)
}
wen := wen >> UFix(1)
when (mem_wen) {
when (!io.ctrl.killm) {
wen := (wen >> UFix(1)) | (UFix(1) << mem_fu_latency)
@ -613,9 +604,6 @@ class rocketFPU(sfma_latency: Int, dfma_latency: Int) extends Component
}
}
}
.otherwise {
wen := wen >> UFix(1)
}
val wsrc = winfo(0)(1,0)
val wdata = Mux(wsrc === UFix(0), dfma.io.out, // DFMA
@ -629,19 +617,19 @@ class rocketFPU(sfma_latency: Int, dfma_latency: Int) extends Component
val waddr = winfo(0).toUFix >> UFix(2)
regfile.write(waddr, wdata, wen(0))
when (wb_toint_val || wen(0)) {
when (wb_reg_valid && wb_ctrl.toint || wen(0)) {
fsr_exc := fsr_exc |
Fill(fsr_exc.getWidth, wb_toint_val) & wb_toint_exc |
Fill(fsr_exc.getWidth, wb_reg_valid && wb_ctrl.toint) & wb_toint_exc |
Fill(fsr_exc.getWidth, wen(0)) & wexc
}
when (wb_wrfsr_val) {
when (wb_reg_valid && wb_ctrl.wrfsr) {
fsr_exc := fastpipe.io.out_s(4,0)
fsr_rm := fastpipe.io.out_s(7,5)
}
val fp_inflight = mem_toint_val || wb_toint_val || mem_wen || wen.orR
val fsr_busy = ctrl.rdfsr && fp_inflight || mem_wrfsr_val || wb_wrfsr_val
val units_busy = Bool(false)
val fp_inflight = mem_reg_valid && mem_ctrl.toint || wb_reg_valid && wb_ctrl.toint || mem_wen || wen.orR
val fsr_busy = ctrl.rdfsr && fp_inflight || mem_reg_valid && mem_ctrl.wrfsr || wb_reg_valid && wb_ctrl.wrfsr
val units_busy = mem_reg_valid && mem_ctrl.fma && (io.sfma.valid && mem_ctrl.single || io.dfma.valid && !mem_ctrl.single)
io.ctrl.nack := fsr_busy || units_busy || write_port_busy
io.ctrl.dec <> fp_decoder.io.sigs
// we don't currently support round-max-magnitude (rm=4)