riscv/rocket-chip
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add fsgnj[n|x].[s|d]

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This commit is contained in:
Andrew Waterman
2012-02-14 04:24:35 -08:00
parent 1d604bcd49
commit ce202c73d1
1 changed files with 122 additions and 87 deletions
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209
rocket/src/main/scala/fpu.scala
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@@ -12,9 +12,9 @@ object rocketFPConstants
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_SGNJ = Bits("b000101")
val FCMD_SGNJN = Bits("b000110")
val FCMD_SGNJX = Bits("b000111")
val FCMD_CVT_L_FMT = Bits("b001000")
val FCMD_CVT_LU_FMT = Bits("b001001")
val FCMD_CVT_W_FMT = Bits("b001010")
@@ -108,7 +108,13 @@ class rocketFPUDecoder extends Component
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)
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)
// 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),
@@ -232,53 +238,77 @@ class rocketFPIntUnit extends Component
io.exc := Mux(io.single, exc_s, exc_d)
}
class rocketIntFPUnit extends Component
class rocketFPUFastPipe 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(64, INPUT)
val out = Bits(65, OUTPUT)
val exc = Bits(5, OUTPUT)
val fromint = Bits(64, INPUT)
val in1 = Bits(65, INPUT)
val in2 = Bits(65, INPUT)
val out_s = Bits(65, OUTPUT)
val exc_s = Bits(5, OUTPUT)
val out_d = Bits(65, OUTPUT)
val exc_d = Bits(5, OUTPUT)
}
// int->fp units
val rec_s = new hardfloat.float32ToRecodedFloat32
val rec_d = new hardfloat.float64ToRecodedFloat64
rec_s.io.in := io.in
rec_d.io.in := io.in
rec_s.io.in := io.fromint
rec_d.io.in := io.fromint
val i2s = new hardfloat.anyToRecodedFloat32
i2s.io.in := io.in
i2s.io.in := io.fromint
i2s.io.roundingMode := io.fsr >> UFix(5)
i2s.io.typeOp := ~io.cmd(1,0)
val i2d = new hardfloat.anyToRecodedFloat64
i2d.io.in := io.in
i2d.io.in := io.fromint
i2d.io.roundingMode := io.fsr >> UFix(5)
i2d.io.typeOp := ~io.cmd(1,0)
// fp->fp units
val sign_s = Mux(io.cmd === FCMD_SGNJ, io.in2(32),
Mux(io.cmd === FCMD_SGNJN, ~io.in2(32),
io.in1(32) ^ io.in2(32))) // FCMD_SGNJX
val sign_d = Mux(io.cmd === FCMD_SGNJ, io.in2(64),
Mux(io.cmd === FCMD_SGNJN, ~io.in2(64),
io.in1(64) ^ io.in2(64))) // FCMD_SGNJX
val fsgnj = Cat(Mux(io.single, io.in1(64), sign_d), io.in1(63,33),
Mux(io.single, sign_s, io.in1(32)), io.in1(31,0))
// output muxing
val (out_s, exc_s) = (Wire() { Bits() }, Wire() { Bits() })
out_s := rec_s.io.out
out_s := Reg(rec_s.io.out)
exc_s := Bits(0)
val (out_d, exc_d) = (Wire() { Bits() }, Wire() { Bits() })
out_d := rec_d.io.out
out_d := Reg(rec_d.io.out)
exc_d := Bits(0)
when (io.cmd === FCMD_MTFSR || io.cmd === FCMD_MFFSR) {
out_s := io.in(FSR_WIDTH-1,0)
val r_cmd = Reg(io.cmd)
when (r_cmd === FCMD_MTFSR || r_cmd === FCMD_MFFSR) {
out_s := Reg(io.fromint(FSR_WIDTH-1,0))
}
when (io.cmd === FCMD_CVT_FMT_W || io.cmd === FCMD_CVT_FMT_WU ||
io.cmd === FCMD_CVT_FMT_L || io.cmd === FCMD_CVT_FMT_LU) {
out_s := i2s.io.out
exc_s := i2s.io.exceptionFlags
out_d := i2d.io.out
exc_d := i2d.io.exceptionFlags
when (r_cmd === FCMD_SGNJ || r_cmd === FCMD_SGNJN || r_cmd === FCMD_SGNJX) {
val r_fsgnj = Reg(fsgnj)
out_s := r_fsgnj(32,0)
out_d := r_fsgnj
}
when (r_cmd === FCMD_CVT_FMT_W || r_cmd === FCMD_CVT_FMT_WU ||
r_cmd === FCMD_CVT_FMT_L || r_cmd === FCMD_CVT_FMT_LU) {
out_s := Reg(i2s.io.out)
exc_s := Reg(i2s.io.exceptionFlags)
out_d := Reg(i2d.io.out)
exc_d := Reg(i2d.io.exceptionFlags)
}
io.out := Mux(io.single, Cat(Fill(32,UFix(1)), out_s), out_d)
io.exc := Mux(io.single, exc_s, exc_d)
io.out_s := Cat(Fill(32,UFix(1)), out_s)
io.exc_s := exc_s
io.out_d := out_d
io.exc_d := exc_d
}
class rocketFPU(sfma_latency: Int, dfma_latency: Int) extends Component
@@ -301,6 +331,7 @@ class rocketFPU(sfma_latency: Int, dfma_latency: Int) extends Component
when (io.ctrl.valid) {
ctrl := fp_decoder.io.sigs
}
val mem_ctrl = Reg(ctrl)
// load response
val load_wb = Reg(io.dpath.dmem_resp_val, resetVal = Bool(false))
@@ -330,109 +361,99 @@ class rocketFPU(sfma_latency: Int, dfma_latency: Int) extends Component
val ex_rs2 = regfile.read(reg_inst(21,17))
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_wrfsr_val = Reg(resetVal = Bool(false))
val fp_cmp_data = Reg() { Bits() }
val fp_toint_single = Reg() { Bool() }
val fp_toint_cmd = Reg() { Bits() }
val fp_waddr = Reg() { Bits() }
val mem_fromint_val = Reg(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_wrfsr_val = Reg(resetVal = Bool(false))
fp_fromint_val := Bool(false)
fp_toint_val := Bool(false)
fp_wrfsr_val := Bool(false)
mem_fromint_val := Bool(false)
mem_toint_val := Bool(false)
mem_wrfsr_val := Bool(false)
when (reg_valid) {
fp_waddr := reg_inst(31,27)
when (ctrl.fromint || ctrl.wrfsr) {
fp_fromint_val := !io.ctrl.killx
fp_fromint_data := io.dpath.fromint_data
mem_fromint_val := !io.ctrl.killx
mem_fromint_data := io.dpath.fromint_data
}
when (ctrl.wrfsr) {
fp_wrfsr_val := !io.ctrl.killx
mem_wrfsr_val := !io.ctrl.killx
}
when (ctrl.toint) {
fp_toint_val := !io.ctrl.killx
mem_toint_val := !io.ctrl.killx
}
when (ctrl.toint || ctrl.fastpipe) {
fp_toint_data := ex_rs1
mem_rs1 := ex_rs1
when (ctrl.ren2) {
fp_cmp_data := ex_rs2
mem_rs2 := ex_rs2
}
}
when (ctrl.store) {
fp_toint_data := ex_rs2
when (ctrl.ren1) {
mem_rs1 := ex_rs1
}
when (ctrl.toint || ctrl.store) {
fp_toint_single := ctrl.single
fp_toint_cmd := ctrl.cmd
when (ctrl.ren2) {
mem_rs2 := ex_rs2
}
when (ctrl.ren3) {
mem_rs3 := ex_rs3
}
when (ctrl.store) {
mem_rs1 := ex_rs2
}
}
// currently we assume FP stores and FP->int ops take 1 cycle (MEM)
val fpiu = new rocketFPIntUnit
fpiu.io.single := ctrl.single
fpiu.io.cmd := ctrl.cmd
fpiu.io.single := mem_ctrl.single
fpiu.io.cmd := mem_ctrl.cmd
fpiu.io.fsr := Cat(fsr_rm, fsr_exc)
fpiu.io.in1 := fp_toint_data
fpiu.io.in2 := fp_cmp_data
fpiu.io.in1 := mem_rs1
fpiu.io.in2 := mem_rs2
io.dpath.store_data := fpiu.io.store_data
io.dpath.toint_data := fpiu.io.toint_data
val ifpu = new rocketIntFPUnit
ifpu.io.single := ctrl.single
ifpu.io.cmd := ctrl.cmd
ifpu.io.fsr := Cat(fsr_rm, fsr_exc)
ifpu.io.in := fp_fromint_data
val fastpipe = new rocketFPUFastPipe
fastpipe.io.single := mem_ctrl.single
fastpipe.io.cmd := mem_ctrl.cmd
fastpipe.io.fsr := Cat(fsr_rm, fsr_exc)
fastpipe.io.fromint := mem_fromint_data
fastpipe.io.in1 := mem_rs1
fastpipe.io.in2 := mem_rs2
val retire_wrfsr = Reg(!io.ctrl.killm && fp_wrfsr_val, resetVal = 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_exc = Reg(ifpu.io.exc)
val retire_fromint_wdata = Reg(ifpu.io.out)
val retire_fromint_waddr = Reg(fp_waddr)
when (retire_toint || retire_fromint) {
fsr_exc := fsr_exc |
Fill(fsr_exc.getWidth, retire_toint) & retire_toint_exc |
Fill(fsr_exc.getWidth, retire_fromint) & retire_fromint_exc
}
when (retire_wrfsr) { // MTFSR
fsr_exc := retire_fromint_wdata(4,0)
fsr_rm := retire_fromint_wdata(7,5)
}
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_toint_exc = Reg(fpiu.io.exc)
// writeback arbitration
val wen = Reg(resetVal = Bits(0, dfma_latency-1))
val winfo = Vec(dfma_latency-1) { Reg() { Bits() } }
val mem_stage_wen = Reg(resetVal = Bool(false))
val mem_wen = Reg(resetVal = Bool(false))
val fastpipe_latency = 2
require(fastpipe_latency < sfma_latency && sfma_latency <= dfma_latency)
val ex_stage_fu_latency = Mux(ctrl.fastpipe, UFix(fastpipe_latency-1),
Mux(ctrl.single, UFix(sfma_latency-1),
UFix(dfma_latency-1)))
val mem_stage_fu_latency = Reg(ex_stage_fu_latency - UFix(1))
val mem_fu_latency = Reg(ex_stage_fu_latency - UFix(1))
val write_port_busy = ctrl.fastpipe && wen(fastpipe_latency-1) ||
Bool(sfma_latency < dfma_latency) && ctrl.fma && ctrl.single && wen(sfma_latency-1) ||
mem_stage_wen && mem_stage_fu_latency === ex_stage_fu_latency
mem_stage_wen := reg_valid && !io.ctrl.killx && (ctrl.fma || ctrl.fastpipe)
mem_wen && mem_fu_latency === ex_stage_fu_latency
mem_wen := reg_valid && !io.ctrl.killx && (ctrl.fma || ctrl.fastpipe)
val ex_stage_wsrc = Cat(ctrl.fastpipe, ctrl.single)
val mem_stage_winfo = Reg(Cat(reg_inst(31,27), ex_stage_wsrc))
val mem_winfo = Reg(Cat(reg_inst(31,27), ex_stage_wsrc))
for (i <- 0 until dfma_latency-2) {
winfo(i) := winfo(i+1)
}
when (mem_stage_wen) {
when (mem_wen) {
when (!io.ctrl.killm) {
wen := (wen >> UFix(1)) | (UFix(1) << mem_stage_fu_latency)
wen := (wen >> UFix(1)) | (UFix(1) << mem_fu_latency)
}
for (i <- 0 until dfma_latency-1) {
when (UFix(i) === mem_stage_fu_latency) {
winfo(i) := mem_stage_winfo
when (UFix(i) === mem_fu_latency) {
winfo(i) := mem_winfo
}
}
}
@@ -443,13 +464,27 @@ class rocketFPU(sfma_latency: Int, dfma_latency: Int) extends Component
val wsrc = winfo(0)(1,0)
val wdata = Mux(wsrc === UFix(0), UFix(0), // DFMA
Mux(wsrc === UFix(1), UFix(0), // SFMA
Mux(wsrc === UFix(2), retire_fromint_wdata,
retire_fromint_wdata)))
Mux(wsrc === UFix(2), fastpipe.io.out_d,
fastpipe.io.out_s)))
val wexc = Mux(wsrc === UFix(0), Bits(0), // DFMA
Mux(wsrc === UFix(1), Bits(0), // SFMA
Mux(wsrc === UFix(2), fastpipe.io.exc_d,
fastpipe.io.exc_s)))
val waddr = winfo(0) >> UFix(2)
regfile.write(waddr, wdata, wen(0))
val fp_inflight = fp_toint_val || retire_toint || mem_stage_wen || wen.orR
val fsr_busy = ctrl.rdfsr && fp_inflight || fp_wrfsr_val || retire_wrfsr
when (wb_toint_val || wen(0)) {
fsr_exc := fsr_exc |
Fill(fsr_exc.getWidth, wb_toint_val) & wb_toint_exc |
Fill(fsr_exc.getWidth, wen(0)) & wexc
}
when (wb_wrfsr_val) {
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)
io.ctrl.nack := fsr_busy || units_busy || write_port_busy
io.ctrl.dec <> fp_decoder.io.sigs