riscv/rocket-chip
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fixes for div/mul hazard checking + cleanup

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This commit is contained in:
Rimas Avizienis 2011-11-01 23:14:34 -07:00
parent d8ffecf565
commit 7a528d6255
4 changed files with 249 additions and 263 deletions
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48
rocket/src/main/scala/cpu.scala
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@ -40,63 +40,23 @@ class rocketProc extends Component
val ctrl = new rocketCtrl(); val ctrl = new rocketCtrl();
val dpath = new rocketDpath(); val dpath = new rocketDpath();
// val mem = new rocketMemory();
// val wb = new rocketWriteback();
ctrl.io.dpath <> dpath.io.ctrl; ctrl.io.dpath <> dpath.io.ctrl;
ctrl.io.dmem ^^ io.dmem;
ctrl.io.host.start ^^ io.host.start; ctrl.io.host.start ^^ io.host.start;
ctrl.io.imem ^^ io.imem; ctrl.io.imem ^^ io.imem;
dpath.io.dmem ^^ io.dmem;
dpath.io.imem.req_addr ^^ io.imem.req_addr; dpath.io.imem.req_addr ^^ io.imem.req_addr;
dpath.io.imem.resp_data ^^ io.imem.resp_data; dpath.io.imem.resp_data ^^ io.imem.resp_data;
dpath.io.host ^^ io.host; dpath.io.host ^^ io.host;
dpath.io.debug ^^ io.debug; dpath.io.debug ^^ io.debug;
ctrl.io.dmem ^^ io.dmem; // FIXME: console disconnected
dpath.io.dmem ^^ io.dmem;
// FIXME
// io.console.bits := dpath.io.dpath.rs1(7,0); // io.console.bits := dpath.io.dpath.rs1(7,0);
io.console.bits := Bits(0,8); io.console.bits := Bits(0,8);
io.console.valid := ctrl.io.console.valid; io.console.valid := ctrl.io.console.valid;
ctrl.io.console.rdy := io.console.rdy; ctrl.io.console.rdy := io.console.rdy;
// dpath.io.wb <> wb.io;
// dpath.io.wb.wen <> wb.io.wb_wen;
// dpath.io.wb.waddr <> wb.io.wb_waddr;
// dpath.io.wb.wdata <> wb.io.wb_wdata;
// ctrl.io.mem.mrq_val <> mem.io.mem_mrq_val;
// ctrl.io.mem.mrq_cmd <> mem.io.mem_mrq_cmd;
// ctrl.io.mem.mrq_type <> mem.io.mem_mrq_type;
// ctrl.io.mem.mrq_deq <> mem.io.mem_mrq_deq;
// ctrl.io.mem.xsdq_rdy <> mem.io.mem_xsdq_rdy;
// ctrl.io.mem.xsdq_val <> mem.io.mem_xsdq_val;
// ctrl.io.mem.dc_busy := !io.dmem.req_rdy;
// ctrl.io.console ^^ io.console;
// ctrl.io.wb.waddr <> wb.io.wb_waddr;
// ctrl.io.wb.wen <> wb.io.wb_wen;
// TODO: SHOULD BE THE FOLLOWING BUT NEED BETTER INTERFACE CHUNKS
// mem.io.dmem >< io.dmem;
// mem.io.dmem_req_val ^^ io.dmem.req_val;
// mem.io.dmem_req_rdy ^^ io.dmem.req_rdy;
// mem.io.dmem_req_op ^^ io.dmem.req_op;
// mem.io.dmem_req_addr ^^ io.dmem.req_addr;
// mem.io.dmem_req_data ^^ io.dmem.req_data;
// mem.io.dmem_req_wmask ^^ io.dmem.req_wmask;
// mem.io.dmem_req_tag ^^ io.dmem.req_tag;
//
// mem.io.dpath_rs2 <> dpath.io.dpath.rs2;
// mem.io.dpath_waddr <> dpath.io.dpath.waddr;
// mem.io.dpath_alu_out <> dpath.io.dpath.alu_out;
// wb.io.dmem_resp_val ^^ io.dmem.resp_val;
// wb.io.dmem_resp_data ^^ io.dmem.resp_data;
// wb.io.dmem_resp_tag ^^ io.dmem.resp_tag;
} }
} }

126
rocket/src/main/scala/ctrl.scala
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@ -41,6 +41,7 @@ class ioCtrlDpath extends Bundle()
val mem_load = Bool('output); val mem_load = Bool('output);
val dcache_miss = Bool('output); val dcache_miss = Bool('output);
val wen = Bool('output); val wen = Bool('output);
val wb_div_mul = Bool('output);
// inputs from datapath // inputs from datapath
val btb_hit = Bool('input); val btb_hit = Bool('input);
val inst = Bits(32, 'input); val inst = Bits(32, 'input);
@ -52,10 +53,11 @@ class ioCtrlDpath extends Bundle()
val mul_result_val = Bool('input); val mul_result_val = Bool('input);
val ex_waddr = UFix(5,'input); // write addr from execute stage val ex_waddr = UFix(5,'input); // write addr from execute stage
val mem_waddr = UFix(5,'input); // write addr from memory stage val mem_waddr = UFix(5,'input); // write addr from memory stage
val wb_waddr = UFix(5,'input); // write addr from writeback stage
val exception = Bool('input); val exception = Bool('input);
val status = Bits(8, 'input); val status = Bits(8, 'input);
val sboard_set = Bool('input); // val sboard_set = Bool('input);
val sboard_seta = UFix(5, 'input); // val sboard_seta = UFix(5, 'input);
val sboard_clr0 = Bool('input); val sboard_clr0 = Bool('input);
val sboard_clr0a = UFix(5, 'input); val sboard_clr0a = UFix(5, 'input);
val sboard_clr1 = Bool('input); val sboard_clr1 = Bool('input);
@ -205,13 +207,21 @@ class rocketCtrl extends Component
val console_out_fire = id_console_out_val & ~io.dpath.killd; val console_out_fire = id_console_out_val & ~io.dpath.killd;
io.console.valid := console_out_fire.toBool; io.console.valid := console_out_fire.toBool;
val wb_reg_div_mul_val = Reg(){Bool()};
val dcache_miss = Reg(){Bool()};
val sboard = new rocketCtrlSboard(); val sboard = new rocketCtrlSboard();
sboard.io.raddra := id_raddr2.toUFix; sboard.io.raddra := id_raddr2.toUFix;
sboard.io.raddrb := id_raddr1.toUFix; sboard.io.raddrb := id_raddr1.toUFix;
sboard.io.raddrc := id_waddr.toUFix; sboard.io.raddrc := id_waddr.toUFix;
sboard.io.set := io.dpath.sboard_set; // sboard.io.set := io.dpath.sboard_set;
sboard.io.seta := io.dpath.sboard_seta; // sboard.io.seta := io.dpath.sboard_seta;
// scoreboard set (for D$ misses, div, mul)
sboard.io.set := wb_reg_div_mul_val | dcache_miss;
sboard.io.seta := io.dpath.wb_waddr;
sboard.io.clr0 := io.dpath.sboard_clr0; sboard.io.clr0 := io.dpath.sboard_clr0;
sboard.io.clr0a := io.dpath.sboard_clr0a; sboard.io.clr0a := io.dpath.sboard_clr0a;
sboard.io.clr1 := io.dpath.sboard_clr1; sboard.io.clr1 := io.dpath.sboard_clr1;
@ -222,14 +232,15 @@ class rocketCtrl extends Component
val id_stall_waddr = sboard.io.stallc; val id_stall_waddr = sboard.io.stallc;
val id_stall_ra = sboard.io.stallra; val id_stall_ra = sboard.io.stallra;
val id_reg_btb_hit = Reg(width = 1, resetVal = Bool(false)); val id_reg_btb_hit = Reg(width = 1, resetVal = Bool(false));
val ex_reg_br_type = Reg(){UFix(width = 4)}; val ex_reg_br_type = Reg(){UFix(width = 4)};
val ex_reg_btb_hit = Reg(){Bool()}; val ex_reg_btb_hit = Reg(){Bool()};
val ex_reg_mem_val = Reg(){Bool()}; val ex_reg_div_mul_val = Reg(){Bool()};
val ex_reg_mem_cmd = Reg(){UFix(width = 4)}; val ex_reg_mem_val = Reg(){Bool()};
val ex_reg_mem_type = Reg(){UFix(width = 3)}; val ex_reg_mem_cmd = Reg(){UFix(width = 4)};
val ex_reg_eret = Reg(resetVal = Bool(false)); val ex_reg_mem_type = Reg(){UFix(width = 3)};
val ex_reg_privileged = Reg(resetVal = Bool(false)); val ex_reg_eret = Reg(resetVal = Bool(false));
val ex_reg_privileged = Reg(resetVal = Bool(false));
when (!io.dpath.stalld) { when (!io.dpath.stalld) {
when (io.dpath.killf) { when (io.dpath.killf) {
@ -241,22 +252,24 @@ class rocketCtrl extends Component
} }
when (reset.toBool || io.dpath.killd) { when (reset.toBool || io.dpath.killd) {
ex_reg_br_type <== BR_N; ex_reg_br_type <== BR_N;
ex_reg_btb_hit <== Bool(false); ex_reg_btb_hit <== Bool(false);
ex_reg_mem_val <== Bool(false); ex_reg_div_mul_val <== Bool(false);
ex_reg_mem_cmd <== UFix(0, 4); ex_reg_mem_val <== Bool(false);
ex_reg_mem_type <== UFix(0, 3); ex_reg_mem_cmd <== UFix(0, 4);
ex_reg_eret <== Bool(false); ex_reg_mem_type <== UFix(0, 3);
ex_reg_privileged <== Bool(false); ex_reg_eret <== Bool(false);
ex_reg_privileged <== Bool(false);
} }
otherwise { otherwise {
ex_reg_br_type <== id_br_type; ex_reg_br_type <== id_br_type;
ex_reg_btb_hit <== id_reg_btb_hit; ex_reg_btb_hit <== id_reg_btb_hit;
ex_reg_mem_val <== id_mem_val.toBool; ex_reg_div_mul_val <== id_div_val.toBool || id_mul_val.toBool;
ex_reg_mem_cmd <== id_mem_cmd; ex_reg_mem_val <== id_mem_val.toBool;
ex_reg_mem_type <== id_mem_type; ex_reg_mem_cmd <== id_mem_cmd;
ex_reg_eret <== id_eret.toBool; ex_reg_mem_type <== id_mem_type;
ex_reg_privileged <== id_privileged.toBool; ex_reg_eret <== id_eret.toBool;
ex_reg_privileged <== id_privileged.toBool;
} }
val beq = io.dpath.br_eq; val beq = io.dpath.br_eq;
@ -283,31 +296,42 @@ class rocketCtrl extends Component
io.dmem.req_val := ex_reg_mem_val && ~io.dpath.killx; io.dmem.req_val := ex_reg_mem_val && ~io.dpath.killx;
io.dmem.req_cmd := ex_reg_mem_cmd; io.dmem.req_cmd := ex_reg_mem_cmd;
io.dmem.req_type := ex_reg_mem_type; io.dmem.req_type := ex_reg_mem_type;
val mem_reg_mem_val = Reg(){Bool()}; val mem_reg_div_mul_val = Reg(){Bool()};
val mem_reg_mem_cmd = Reg(){UFix(width = 4)}; val mem_reg_mem_val = Reg(){Bool()};
val mem_reg_mem_type = Reg(){UFix(width = 3)}; val mem_reg_mem_cmd = Reg(){UFix(width = 4)};
val mem_reg_mem_type = Reg(){UFix(width = 3)};
when (reset.toBool || io.dpath.killx) { when (reset.toBool || io.dpath.killx) {
mem_reg_mem_val <== Bool(false); mem_reg_div_mul_val <== Bool(false);
mem_reg_mem_cmd <== UFix(0, 4); mem_reg_mem_val <== Bool(false);
mem_reg_mem_type <== UFix(0, 3); mem_reg_mem_cmd <== UFix(0, 4);
mem_reg_mem_type <== UFix(0, 3);
} }
otherwise { otherwise {
mem_reg_mem_val <== ex_reg_mem_val; mem_reg_div_mul_val <== ex_reg_div_mul_val;
mem_reg_mem_cmd <== ex_reg_mem_cmd; mem_reg_mem_val <== ex_reg_mem_val;
mem_reg_mem_type <== ex_reg_mem_type; mem_reg_mem_cmd <== ex_reg_mem_cmd;
mem_reg_mem_type <== ex_reg_mem_type;
} }
when (reset.toBool || io.dpath.killm) {
wb_reg_div_mul_val <== Bool(false);
}
otherwise {
wb_reg_div_mul_val <== mem_reg_div_mul_val;
}
// replay PC when the D$ is blocked // replay PC when the D$ is blocked
val replay_mem_pc = mem_reg_mem_val && !io.dmem.req_rdy; val replay_mem_pc = mem_reg_mem_val && !io.dmem.req_rdy;
// replay PC+4 on a D$ load miss // replay PC+4 on a D$ load miss
val mem_cmd_load = mem_reg_mem_val && (mem_reg_mem_cmd === M_XRD); val mem_cmd_load = mem_reg_mem_val && (mem_reg_mem_cmd === M_XRD);
val replay_mem_pc_plus4 = mem_cmd_load && !io.dmem.resp_val; val replay_mem_pc_plus4 = mem_cmd_load && !io.dmem.resp_val;
val dcache_miss = Reg(replay_mem_pc_plus4);
val replay_mem = replay_mem_pc | replay_mem_pc_plus4; val replay_mem = replay_mem_pc | replay_mem_pc_plus4;
io.dpath.mem_load := mem_cmd_load; dcache_miss <== replay_mem_pc_plus4;
io.dpath.mem_load := mem_cmd_load;
io.dpath.dcache_miss := dcache_miss; io.dpath.dcache_miss := dcache_miss;
io.dpath.sel_pc := io.dpath.sel_pc :=
@ -342,8 +366,7 @@ class rocketCtrl extends Component
io.dpath.stalld io.dpath.stalld
); );
// check for loads in execute stage to detect load/use hazards // check for loads in execute and mem stages to detect load/use hazards
val ex_mem_cmd_load = ex_reg_mem_val && (ex_reg_mem_cmd === M_XRD); val ex_mem_cmd_load = ex_reg_mem_val && (ex_reg_mem_cmd === M_XRD);
val lu_stall_raddr1_ex = val lu_stall_raddr1_ex =
@ -374,9 +397,28 @@ class rocketCtrl extends Component
id_ren2.toBool && id_ren2.toBool &&
(id_raddr2 === io.dpath.mem_waddr); (id_raddr2 === io.dpath.mem_waddr);
// check for divide and multiply instructions in ex,mem,wb stages
val dm_stall_ex =
ex_reg_div_mul_val &&
((id_ren1.toBool && (id_raddr1 === io.dpath.ex_waddr)) ||
(id_ren2.toBool && (id_raddr2 === io.dpath.ex_waddr)));
val dm_stall_mem =
mem_reg_div_mul_val &&
((id_ren1.toBool && (id_raddr1 === io.dpath.mem_waddr)) ||
(id_ren2.toBool && (id_raddr2 === io.dpath.mem_waddr)));
val dm_stall_wb =
wb_reg_div_mul_val &&
((id_ren1.toBool && (id_raddr1 === io.dpath.wb_waddr)) ||
(id_ren2.toBool && (id_raddr2 === io.dpath.wb_waddr)));
val dm_stall = dm_stall_ex || dm_stall_mem || dm_stall_wb;
val ctrl_stalld = val ctrl_stalld =
~take_pc & ~take_pc &
( (
dm_stall |
lu_stall_raddr1_ex | lu_stall_raddr1_ex |
lu_stall_raddr2_ex | lu_stall_raddr2_ex |
lu_stall_raddr1_mem | lu_stall_raddr1_mem |
@ -396,7 +438,7 @@ class rocketCtrl extends Component
io.dpath.mul_result_val io.dpath.mul_result_val
); );
val ctrl_killd = take_pc | ctrl_stalld; val ctrl_killd = take_pc | ctrl_stalld | io.dpath.killx;
// for divider, multiplier writeback // for divider, multiplier writeback
val mul_wb = io.dpath.mul_result_val; val mul_wb = io.dpath.mul_result_val;

322
rocket/src/main/scala/dcache.scala
View File

@ -91,165 +91,6 @@ class rocketDCacheDM_flush(lines: Int, addrbits: Int) extends Component {
} }
// basic direct mapped data cache, 2 cycle read latency
// parameters :
// lines = # of cache lines
// addr_bits = address width (word addressable) bits
// 64 bit wide cpu port, 128 bit wide memory port, 64 byte cachelines
/*
class rocketDCacheDM(lines: Int, addrbits: Int) extends Component {
val io = new ioDCacheDM();
val indexbits = ceil(log10(lines)/log10(2)).toInt;
val offsetbits = 6;
val tagmsb = addrbits - 1;
val taglsb = indexbits+offsetbits;
val indexmsb = taglsb-1;
val indexlsb = offsetbits;
val offsetmsb = indexlsb-1;
val offsetlsb = 3;
val s_reset :: s_ready :: s_start_writeback :: s_writeback :: s_req_refill :: s_refill :: s_resolve_miss :: Nil = Enum(7) { UFix() };
val state = Reg(resetVal = s_reset);
val r_cpu_req_addr = Reg(Bits(0, addrbits));
val r_r_cpu_req_addr = Reg(r_cpu_req_addr);
val r_cpu_req_val = Reg(Bool(false));
val r_cpu_req_data = Reg(Bits(0,64));
val r_cpu_req_cmd = Reg(Bits(0,4));
val r_cpu_req_wmask = Reg(Bits(0,8));
val r_cpu_req_tag = Reg(Bits(0,12));
val r_cpu_resp_tag = Reg(r_cpu_req_tag);
val r_cpu_resp_val = Reg(Bool(false));
when (io.cpu.req_val && io.cpu.req_rdy) {
r_cpu_req_addr <== io.cpu.req_addr;
r_cpu_req_data <== io.cpu.req_data;
r_cpu_req_cmd <== io.cpu.req_cmd;
r_cpu_req_wmask <== io.cpu.req_wmask;
r_cpu_req_tag <== io.cpu.req_tag; }
val req_load = (r_cpu_req_cmd === M_XRD);
val req_store = (r_cpu_req_cmd === M_XWR);
val req_flush = (r_cpu_req_cmd === M_FLA);
when (io.cpu.req_rdy) { r_cpu_req_val <== io.cpu.req_val; }
otherwise { r_cpu_req_val <== Bool(false); }
// counter
val rr_count = Reg(resetVal = UFix(0,2));
val rr_count_next = rr_count + UFix(1);
when (((state === s_refill) && io.mem.resp_val) || ((state === s_writeback) && io.mem.req_rdy))
{ rr_count <== rr_count_next; }
// tag array
val tag_we = (state === s_resolve_miss);
val tag_waddr = r_cpu_req_addr(indexmsb, indexlsb).toUFix;
val tag_wdata = r_cpu_req_addr(tagmsb, taglsb);
val tag_array = Mem(lines, tag_we, tag_waddr, tag_wdata);
val tag_raddr = Mux((state === s_ready), io.cpu.req_addr(indexmsb, indexlsb).toUFix, r_cpu_req_addr(indexmsb, indexlsb).toUFix);
val tag_rdata = Reg(tag_array.read(tag_raddr));
// valid bit array
val vb_array = Reg(resetVal = Bits(0, lines));
val vb_rdata = Reg(vb_array(tag_raddr));
when (tag_we && !req_flush) { vb_array <== vb_array.bitSet(r_cpu_req_addr(indexmsb, indexlsb).toUFix, UFix(1,1)); }
when (tag_we && req_flush) { vb_array <== vb_array.bitSet(r_cpu_req_addr(indexmsb, indexlsb).toUFix, UFix(0,1)); }
val tag_valid = vb_rdata.toBool;
val tag_match = tag_valid && !req_flush && (tag_rdata === r_cpu_req_addr(tagmsb, taglsb));
val store = ((state === s_ready) && r_cpu_req_val && req_store && tag_match ) ||
((state === s_resolve_miss) && req_store);
// dirty bit array
val db_array = Reg(resetVal = Bits(0, lines));
val db_rdata = Reg(db_array(tag_raddr));
val tag_dirty = db_rdata.toBool;
when (store) { db_array <== db_array.bitSet(r_cpu_req_addr(indexmsb, indexlsb).toUFix, UFix(1,1)); }
when (tag_we) { db_array <== db_array.bitSet(r_cpu_req_addr(indexmsb, indexlsb).toUFix, UFix(0,1)); }
// data array
val data_array_we = ((state === s_refill) && io.mem.resp_val) || store;
val data_array_waddr = Mux((state === s_refill),
Cat(r_cpu_req_addr(indexmsb, indexlsb), rr_count).toUFix,
r_cpu_req_addr(indexmsb, offsetmsb-1).toUFix);
val data_array_wdata = Mux((state === s_refill), io.mem.resp_data, Cat(r_cpu_req_data, r_cpu_req_data));
val req_wmask_expand = Cat(Fill(8, r_cpu_req_wmask(7)),
Fill(8, r_cpu_req_wmask(6)),
Fill(8, r_cpu_req_wmask(5)),
Fill(8, r_cpu_req_wmask(4)),
Fill(8, r_cpu_req_wmask(3)),
Fill(8, r_cpu_req_wmask(2)),
Fill(8, r_cpu_req_wmask(1)),
Fill(8, r_cpu_req_wmask(0)));
val store_wmask = Mux(r_cpu_req_addr(offsetlsb).toBool,
Cat(req_wmask_expand, Bits(0,64)),
Cat(Bits(0,64), req_wmask_expand));
val data_array_wmask = Mux((state === s_refill), ~Bits(0,128), store_wmask);
val data_array = Mem(lines*4, data_array_we, data_array_waddr, data_array_wdata, wrMask = data_array_wmask, resetVal = null);
val data_array_raddr = Mux((state === s_writeback) && io.mem.req_rdy, Cat(r_cpu_req_addr(indexmsb, indexlsb), rr_count_next).toUFix,
Mux((state === s_start_writeback) || (state === s_writeback), Cat(r_cpu_req_addr(indexmsb, indexlsb), rr_count).toUFix,
r_cpu_req_addr(indexmsb, offsetmsb-1)));
val data_array_rdata = Reg(data_array.read(data_array_raddr));
// output signals
io.cpu.req_rdy := (state === s_ready) && (!r_cpu_req_val || tag_match);
when ((((state === s_ready) && r_cpu_req_val && tag_match) || (state === s_resolve_miss)) && !req_store)
{ r_cpu_resp_val <== Bool(true); }
otherwise { r_cpu_resp_val <== Bool(false); }
io.cpu.resp_val := r_cpu_resp_val;
io.cpu.resp_data := Mux(r_r_cpu_req_addr(offsetlsb).toBool, data_array_rdata(127, 64), data_array_rdata(63,0));
io.cpu.resp_tag := r_cpu_resp_tag;
io.mem.req_val := (state === s_req_refill) || (state === s_writeback);
io.mem.req_rw := (state === s_writeback);
io.mem.req_wdata := data_array_rdata;
io.mem.req_tag := UFix(0);
io.mem.req_addr := Mux(state === s_writeback,
Cat(tag_rdata, r_cpu_req_addr(indexmsb, indexlsb), rr_count).toUFix,
Cat(r_cpu_req_addr(tagmsb, indexlsb), Bits(0,2)).toUFix);
// control state machine
switch (state) {
is (s_reset) {
state <== s_ready;
}
is (s_ready) {
when (~r_cpu_req_val) { state <== s_ready; }
when (r_cpu_req_val & tag_match) { state <== s_ready; }
when (tag_valid & tag_dirty) { state <== s_start_writeback; }
when (req_flush) { state <== s_resolve_miss; }
otherwise { state <== s_req_refill; }
}
is (s_start_writeback) {
state <== s_writeback;
}
is (s_writeback) {
when (io.mem.req_rdy && (rr_count === UFix(3,2))) {
when (req_flush) { state <== s_resolve_miss; }
otherwise { state <== s_req_refill; }
}
}
is (s_req_refill)
{
when (io.mem.req_rdy) { state <== s_refill; }
}
is (s_refill) {
when (io.mem.resp_val && (rr_count === UFix(3,2))) { state <== s_resolve_miss; }
}
is (s_resolve_miss) {
state <== s_ready;
}
}
}
*/
class rocketDCacheDM_1C(lines: Int, addrbits: Int) extends Component { class rocketDCacheDM_1C(lines: Int, addrbits: Int) extends Component {
val io = new ioDCacheDM(); val io = new ioDCacheDM();
@ -270,7 +111,6 @@ class rocketDCacheDM_1C(lines: Int, addrbits: Int) extends Component {
val r_cpu_req_data = Reg(resetVal = Bits(0,64)); val r_cpu_req_data = Reg(resetVal = Bits(0,64));
val r_cpu_req_cmd = Reg(resetVal = Bits(0,4)); val r_cpu_req_cmd = Reg(resetVal = Bits(0,4));
val r_cpu_req_type = Reg(resetVal = Bits(0,3)); val r_cpu_req_type = Reg(resetVal = Bits(0,3));
// val r_cpu_req_wmask = Reg(resetVal = Bits(0,8));
val r_cpu_req_tag = Reg(resetVal = Bits(0,5)); val r_cpu_req_tag = Reg(resetVal = Bits(0,5));
val p_store_data = Reg(resetVal = Bits(0,64)); val p_store_data = Reg(resetVal = Bits(0,64));
@ -287,7 +127,6 @@ class rocketDCacheDM_1C(lines: Int, addrbits: Int) extends Component {
r_cpu_req_data <== io.cpu.req_data; r_cpu_req_data <== io.cpu.req_data;
r_cpu_req_cmd <== io.cpu.req_cmd; r_cpu_req_cmd <== io.cpu.req_cmd;
r_cpu_req_type <== io.cpu.req_type; r_cpu_req_type <== io.cpu.req_type;
// r_cpu_req_wmask <== io.cpu.req_wmask;
r_cpu_req_tag <== io.cpu.req_tag; r_cpu_req_tag <== io.cpu.req_tag;
} }
@ -306,7 +145,6 @@ class rocketDCacheDM_1C(lines: Int, addrbits: Int) extends Component {
} }
// tag array // tag array
// val tag_we = (state === s_resolve_miss);
val tag_we = (state === s_refill) && io.mem.req_rdy && (rr_count === UFix(3,2)); val tag_we = (state === s_refill) && io.mem.req_rdy && (rr_count === UFix(3,2));
val tag_waddr = r_cpu_req_addr(indexmsb, indexlsb).toUFix; val tag_waddr = r_cpu_req_addr(indexmsb, indexlsb).toUFix;
val tag_wdata = r_cpu_req_addr(tagmsb, taglsb); val tag_wdata = r_cpu_req_addr(tagmsb, taglsb);
@ -500,4 +338,164 @@ class rocketDCacheDM_1C(lines: Int, addrbits: Int) extends Component {
} }
} }
// basic direct mapped data cache, 2 cycle read latency
// parameters :
// lines = # of cache lines
// addr_bits = address width (word addressable) bits
// 64 bit wide cpu port, 128 bit wide memory port, 64 byte cachelines
/*
class rocketDCacheDM(lines: Int, addrbits: Int) extends Component {
val io = new ioDCacheDM();
val indexbits = ceil(log10(lines)/log10(2)).toInt;
val offsetbits = 6;
val tagmsb = addrbits - 1;
val taglsb = indexbits+offsetbits;
val indexmsb = taglsb-1;
val indexlsb = offsetbits;
val offsetmsb = indexlsb-1;
val offsetlsb = 3;
val s_reset :: s_ready :: s_start_writeback :: s_writeback :: s_req_refill :: s_refill :: s_resolve_miss :: Nil = Enum(7) { UFix() };
val state = Reg(resetVal = s_reset);
val r_cpu_req_addr = Reg(Bits(0, addrbits));
val r_r_cpu_req_addr = Reg(r_cpu_req_addr);
val r_cpu_req_val = Reg(Bool(false));
val r_cpu_req_data = Reg(Bits(0,64));
val r_cpu_req_cmd = Reg(Bits(0,4));
val r_cpu_req_wmask = Reg(Bits(0,8));
val r_cpu_req_tag = Reg(Bits(0,12));
val r_cpu_resp_tag = Reg(r_cpu_req_tag);
val r_cpu_resp_val = Reg(Bool(false));
when (io.cpu.req_val && io.cpu.req_rdy) {
r_cpu_req_addr <== io.cpu.req_addr;
r_cpu_req_data <== io.cpu.req_data;
r_cpu_req_cmd <== io.cpu.req_cmd;
r_cpu_req_wmask <== io.cpu.req_wmask;
r_cpu_req_tag <== io.cpu.req_tag; }
val req_load = (r_cpu_req_cmd === M_XRD);
val req_store = (r_cpu_req_cmd === M_XWR);
val req_flush = (r_cpu_req_cmd === M_FLA);
when (io.cpu.req_rdy) { r_cpu_req_val <== io.cpu.req_val; }
otherwise { r_cpu_req_val <== Bool(false); }
// counter
val rr_count = Reg(resetVal = UFix(0,2));
val rr_count_next = rr_count + UFix(1);
when (((state === s_refill) && io.mem.resp_val) || ((state === s_writeback) && io.mem.req_rdy))
{ rr_count <== rr_count_next; }
// tag array
val tag_we = (state === s_resolve_miss);
val tag_waddr = r_cpu_req_addr(indexmsb, indexlsb).toUFix;
val tag_wdata = r_cpu_req_addr(tagmsb, taglsb);
val tag_array = Mem(lines, tag_we, tag_waddr, tag_wdata);
val tag_raddr = Mux((state === s_ready), io.cpu.req_addr(indexmsb, indexlsb).toUFix, r_cpu_req_addr(indexmsb, indexlsb).toUFix);
val tag_rdata = Reg(tag_array.read(tag_raddr));
// valid bit array
val vb_array = Reg(resetVal = Bits(0, lines));
val vb_rdata = Reg(vb_array(tag_raddr));
when (tag_we && !req_flush) { vb_array <== vb_array.bitSet(r_cpu_req_addr(indexmsb, indexlsb).toUFix, UFix(1,1)); }
when (tag_we && req_flush) { vb_array <== vb_array.bitSet(r_cpu_req_addr(indexmsb, indexlsb).toUFix, UFix(0,1)); }
val tag_valid = vb_rdata.toBool;
val tag_match = tag_valid && !req_flush && (tag_rdata === r_cpu_req_addr(tagmsb, taglsb));
val store = ((state === s_ready) && r_cpu_req_val && req_store && tag_match ) ||
((state === s_resolve_miss) && req_store);
// dirty bit array
val db_array = Reg(resetVal = Bits(0, lines));
val db_rdata = Reg(db_array(tag_raddr));
val tag_dirty = db_rdata.toBool;
when (store) { db_array <== db_array.bitSet(r_cpu_req_addr(indexmsb, indexlsb).toUFix, UFix(1,1)); }
when (tag_we) { db_array <== db_array.bitSet(r_cpu_req_addr(indexmsb, indexlsb).toUFix, UFix(0,1)); }
// data array
val data_array_we = ((state === s_refill) && io.mem.resp_val) || store;
val data_array_waddr = Mux((state === s_refill),
Cat(r_cpu_req_addr(indexmsb, indexlsb), rr_count).toUFix,
r_cpu_req_addr(indexmsb, offsetmsb-1).toUFix);
val data_array_wdata = Mux((state === s_refill), io.mem.resp_data, Cat(r_cpu_req_data, r_cpu_req_data));
val req_wmask_expand = Cat(Fill(8, r_cpu_req_wmask(7)),
Fill(8, r_cpu_req_wmask(6)),
Fill(8, r_cpu_req_wmask(5)),
Fill(8, r_cpu_req_wmask(4)),
Fill(8, r_cpu_req_wmask(3)),
Fill(8, r_cpu_req_wmask(2)),
Fill(8, r_cpu_req_wmask(1)),
Fill(8, r_cpu_req_wmask(0)));
val store_wmask = Mux(r_cpu_req_addr(offsetlsb).toBool,
Cat(req_wmask_expand, Bits(0,64)),
Cat(Bits(0,64), req_wmask_expand));
val data_array_wmask = Mux((state === s_refill), ~Bits(0,128), store_wmask);
val data_array = Mem(lines*4, data_array_we, data_array_waddr, data_array_wdata, wrMask = data_array_wmask, resetVal = null);
val data_array_raddr = Mux((state === s_writeback) && io.mem.req_rdy, Cat(r_cpu_req_addr(indexmsb, indexlsb), rr_count_next).toUFix,
Mux((state === s_start_writeback) || (state === s_writeback), Cat(r_cpu_req_addr(indexmsb, indexlsb), rr_count).toUFix,
r_cpu_req_addr(indexmsb, offsetmsb-1)));
val data_array_rdata = Reg(data_array.read(data_array_raddr));
// output signals
io.cpu.req_rdy := (state === s_ready) && (!r_cpu_req_val || tag_match);
when ((((state === s_ready) && r_cpu_req_val && tag_match) || (state === s_resolve_miss)) && !req_store)
{ r_cpu_resp_val <== Bool(true); }
otherwise { r_cpu_resp_val <== Bool(false); }
io.cpu.resp_val := r_cpu_resp_val;
io.cpu.resp_data := Mux(r_r_cpu_req_addr(offsetlsb).toBool, data_array_rdata(127, 64), data_array_rdata(63,0));
io.cpu.resp_tag := r_cpu_resp_tag;
io.mem.req_val := (state === s_req_refill) || (state === s_writeback);
io.mem.req_rw := (state === s_writeback);
io.mem.req_wdata := data_array_rdata;
io.mem.req_tag := UFix(0);
io.mem.req_addr := Mux(state === s_writeback,
Cat(tag_rdata, r_cpu_req_addr(indexmsb, indexlsb), rr_count).toUFix,
Cat(r_cpu_req_addr(tagmsb, indexlsb), Bits(0,2)).toUFix);
// control state machine
switch (state) {
is (s_reset) {
state <== s_ready;
}
is (s_ready) {
when (~r_cpu_req_val) { state <== s_ready; }
when (r_cpu_req_val & tag_match) { state <== s_ready; }
when (tag_valid & tag_dirty) { state <== s_start_writeback; }
when (req_flush) { state <== s_resolve_miss; }
otherwise { state <== s_req_refill; }
}
is (s_start_writeback) {
state <== s_writeback;
}
is (s_writeback) {
when (io.mem.req_rdy && (rr_count === UFix(3,2))) {
when (req_flush) { state <== s_resolve_miss; }
otherwise { state <== s_req_refill; }
}
}
is (s_req_refill)
{
when (io.mem.req_rdy) { state <== s_refill; }
}
is (s_refill) {
when (io.mem.resp_val && (rr_count === UFix(3,2))) { state <== s_resolve_miss; }
}
is (s_resolve_miss) {
state <== s_ready;
}
}
}
*/
} }

16
rocket/src/main/scala/dpath.scala
View File

@ -82,8 +82,6 @@ class rocketDpath extends Component
val mem_reg_wdata = Reg(resetVal = Bits(0,64)); val mem_reg_wdata = Reg(resetVal = Bits(0,64));
val mem_reg_raddr2 = Reg(resetVal = UFix(0,5)); val mem_reg_raddr2 = Reg(resetVal = UFix(0,5));
val mem_reg_ctrl_ll_wb = Reg(resetVal = Bool(false)); val mem_reg_ctrl_ll_wb = Reg(resetVal = Bool(false));
val mem_reg_ctrl_div_val = Reg(resetVal = Bool(false));
val mem_reg_ctrl_mul_val = Reg(resetVal = Bool(false));
val mem_reg_ctrl_wen = Reg(resetVal = Bool(false)); val mem_reg_ctrl_wen = Reg(resetVal = Bool(false));
val mem_reg_ctrl_wen_pcr = Reg(resetVal = Bool(false)); val mem_reg_ctrl_wen_pcr = Reg(resetVal = Bool(false));
val mem_reg_ctrl_exception = Reg(resetVal = Bool(false)); val mem_reg_ctrl_exception = Reg(resetVal = Bool(false));
@ -95,8 +93,6 @@ class rocketDpath extends Component
val wb_reg_wdata = Reg(resetVal = Bits(0,64)); val wb_reg_wdata = Reg(resetVal = Bits(0,64));
val wb_reg_ctrl_ll_wb = Reg(resetVal = Bool(false)); val wb_reg_ctrl_ll_wb = Reg(resetVal = Bool(false));
val wb_reg_raddr2 = Reg(resetVal = UFix(0,5)); val wb_reg_raddr2 = Reg(resetVal = UFix(0,5));
val wb_reg_ctrl_div_val = Reg(resetVal = Bool(false));
val wb_reg_ctrl_mul_val = Reg(resetVal = Bool(false));
val wb_reg_ctrl_wen = Reg(resetVal = Bool(false)); val wb_reg_ctrl_wen = Reg(resetVal = Bool(false));
val wb_reg_ctrl_wen_pcr = Reg(resetVal = Bool(false)); val wb_reg_ctrl_wen_pcr = Reg(resetVal = Bool(false));
@ -373,15 +369,11 @@ class rocketDpath extends Component
mem_reg_raddr2 <== ex_reg_raddr2; mem_reg_raddr2 <== ex_reg_raddr2;
when (io.ctrl.killx) { when (io.ctrl.killx) {
mem_reg_ctrl_div_val <== Bool(false);
mem_reg_ctrl_mul_val <== Bool(false);
mem_reg_ctrl_wen <== Bool(false); mem_reg_ctrl_wen <== Bool(false);
mem_reg_ctrl_wen_pcr <== Bool(false); mem_reg_ctrl_wen_pcr <== Bool(false);
mem_reg_ctrl_exception <== Bool(false); mem_reg_ctrl_exception <== Bool(false);
} }
otherwise { otherwise {
mem_reg_ctrl_div_val <== ex_reg_ctrl_div_val;
mem_reg_ctrl_mul_val <== ex_reg_ctrl_mul_val;
mem_reg_ctrl_wen <== ex_reg_ctrl_wen; mem_reg_ctrl_wen <== ex_reg_ctrl_wen;
mem_reg_ctrl_wen_pcr <== ex_reg_ctrl_wen_pcr; mem_reg_ctrl_wen_pcr <== ex_reg_ctrl_wen_pcr;
mem_reg_ctrl_exception <== ex_reg_ctrl_exception; mem_reg_ctrl_exception <== ex_reg_ctrl_exception;
@ -416,14 +408,10 @@ class rocketDpath extends Component
wb_reg_raddr2 <== mem_reg_raddr2; wb_reg_raddr2 <== mem_reg_raddr2;
when (io.ctrl.killm) { when (io.ctrl.killm) {
wb_reg_ctrl_div_val <== Bool(false);
wb_reg_ctrl_mul_val <== Bool(false);
wb_reg_ctrl_wen <== Bool(false); wb_reg_ctrl_wen <== Bool(false);
wb_reg_ctrl_wen_pcr <== Bool(false); wb_reg_ctrl_wen_pcr <== Bool(false);
} }
otherwise { otherwise {
wb_reg_ctrl_div_val <== mem_reg_ctrl_div_val;
wb_reg_ctrl_mul_val <== mem_reg_ctrl_mul_val;
wb_reg_ctrl_wen <== mem_reg_ctrl_wen; wb_reg_ctrl_wen <== mem_reg_ctrl_wen;
wb_reg_ctrl_wen_pcr <== mem_reg_ctrl_wen_pcr; wb_reg_ctrl_wen_pcr <== mem_reg_ctrl_wen_pcr;
} }
@ -453,9 +441,7 @@ class rocketDpath extends Component
rfile.io.w1.en := r_dmem_resp_val; rfile.io.w1.en := r_dmem_resp_val;
rfile.io.w1.data := dmem_resp_data_final; rfile.io.w1.data := dmem_resp_data_final;
// scoreboard set (for D$ misses, div, mul) io.ctrl.wb_waddr := wb_reg_waddr;
io.ctrl.sboard_set := wb_reg_ctrl_div_val | wb_reg_ctrl_mul_val | io.ctrl.dcache_miss;
io.ctrl.sboard_seta := wb_reg_waddr;
// scoreboard clear (for div/mul and D$ load miss writebacks) // scoreboard clear (for div/mul and D$ load miss writebacks)
io.ctrl.sboard_clr0 := wb_reg_ctrl_ll_wb; io.ctrl.sboard_clr0 := wb_reg_ctrl_ll_wb;