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rocket-chip
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made I$ associative

This commit is contained in:
Andrew Waterman 2012-01-24 16:51:30 -08:00
parent aa3465699b
commit 97c379f1d7
3 changed files with 56 additions and 33 deletions
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80
rocket/src/main/scala/icache.scala
View File

@ -27,7 +27,7 @@ class ioIcache(view: List[String] = null) extends Bundle (view)
val resp_val = Bool(OUTPUT);
}
class ioICacheDM extends Bundle()
class ioICache extends Bundle()
{
val cpu = new ioImem();
val mem = new ioIcache().flip();
@ -37,11 +37,12 @@ class ioICacheDM extends Bundle()
// 32 bit wide cpu port, 128 bit wide memory port, 64 byte cachelines
// parameters :
// lines = # cache lines
class rocketICacheDM(lines: Int) extends Component {
val io = new ioICacheDM();
class rocketICache(sets: Int, assoc: Int) extends Component {
val io = new ioICache();
val lines = sets * assoc;
val addrbits = PADDR_BITS;
val indexbits = log2up(lines);
val indexbits = log2up(sets);
val offsetbits = OFFSET_BITS;
val tagmsb = addrbits - 1;
val taglsb = indexbits+offsetbits;
@ -54,15 +55,17 @@ class rocketICacheDM(lines: Int) extends Component {
val rf_cnt_bits = log2up(REFILL_CYCLES);
require(PGIDX_BITS >= taglsb); // virtually-indexed, physically-tagged constraint
require(ispow2(sets) && ispow2(assoc));
val s_reset :: s_ready :: s_request :: s_refill_wait :: s_refill :: Nil = Enum(5) { UFix() };
val state = Reg(resetVal = s_reset);
val r_cpu_req_idx = Reg { Bits(width = PGIDX_BITS) }
val r_cpu_req_ppn = Reg { Bits(width = PPN_BITS) }
val r_cpu_req_idx = Reg { Bits() }
val r_cpu_req_ppn = Reg { Bits() }
val r_cpu_req_val = Reg(resetVal = Bool(false));
val rdy = Wire() { Bool() }
val tag_hit = Wire() { Bool() }
when (io.cpu.req_val && rdy) {
r_cpu_req_val <== Bool(true)
@ -85,41 +88,56 @@ class rocketICacheDM(lines: Int) extends Component {
when (io.mem.resp_val) {
refill_count <== refill_count + UFix(1);
}
val repl_way = LFSR16(state === s_ready && r_cpu_req_val && !io.cpu.itlb_miss && !tag_hit)(log2up(assoc)-1,0)
val word_shift = Cat(r_cpu_req_idx(offsetmsb-rf_cnt_bits,offsetlsb), UFix(0, log2up(databits))).toUFix
val tag_addr =
Mux((state === s_refill_wait), r_cpu_req_idx(indexmsb,indexlsb),
io.cpu.req_idx(indexmsb,indexlsb)).toUFix;
val tag_we = (state === s_refill_wait) && io.mem.resp_val;
val tag_array = Mem4(lines, r_cpu_miss_tag);
tag_array.setReadLatency(1);
tag_array.setTarget('inst);
val tag_rdata = tag_array.rw(tag_addr, r_cpu_miss_tag, tag_we);
// valid bit array
val vb_array = Reg(resetVal = Bits(0, lines));
when (io.cpu.invalidate) {
vb_array <== Bits(0,lines);
}
when (tag_we) {
vb_array <== vb_array.bitSet(r_cpu_req_idx(indexmsb,indexlsb).toUFix, UFix(1,1));
}
val tag_valid = vb_array(r_cpu_req_idx(indexmsb,indexlsb)).toBool;
val tag_hit = tag_valid && (tag_rdata === r_cpu_hit_addr(tagmsb,taglsb))
// data array
val data_addr =
Mux((state === s_refill_wait) || (state === s_refill), Cat(r_cpu_req_idx(indexmsb,offsetbits), refill_count),
io.cpu.req_idx(indexmsb, offsetbits-rf_cnt_bits)).toUFix;
val data_array = Mem4(lines*REFILL_CYCLES, io.mem.resp_data);
data_array.setReadLatency(1);
data_array.setTarget('inst);
val data_array_rdata = data_array.rw(data_addr, io.mem.resp_data, io.mem.resp_val);
val data_mux = new Mux1H(assoc, MEM_DATA_BITS)
var any_hit = Bool(false)
for (i <- 0 until assoc)
{
val repl_me = (repl_way === UFix(i))
val tag_array = Mem4(lines, r_cpu_miss_tag);
tag_array.setReadLatency(1);
tag_array.setTarget('inst);
val tag_rdata = tag_array.rw(tag_addr, r_cpu_miss_tag, tag_we && repl_me);
// valid bit array
val vb_array = Reg(resetVal = Bits(0, lines));
when (io.cpu.invalidate) {
vb_array <== Bits(0,lines);
}
when (tag_we && repl_me) {
vb_array <== vb_array.bitSet(r_cpu_req_idx(indexmsb,indexlsb).toUFix, UFix(1,1));
}
val valid = vb_array(r_cpu_req_idx(indexmsb,indexlsb)).toBool;
val hit = valid && (tag_rdata === r_cpu_hit_addr(tagmsb,taglsb))
// data array
val data_array = Mem4(lines*REFILL_CYCLES, io.mem.resp_data);
data_array.setReadLatency(1);
data_array.setTarget('inst);
val data_out = data_array.rw(data_addr, io.mem.resp_data, io.mem.resp_val && repl_me)
data_mux.io.sel(i) := hit
data_mux.io.in(i) := (data_out >> word_shift)(databits-1,0);
any_hit = any_hit || hit
}
tag_hit := any_hit
// output signals
io.cpu.resp_val := !io.cpu.itlb_miss && (state === s_ready) && r_cpu_req_val && tag_hit;
rdy <== !io.cpu.itlb_miss && (state === s_ready) && (!r_cpu_req_val || tag_hit);
io.cpu.resp_data := data_array_rdata >> Cat(r_cpu_req_idx(offsetmsb-rf_cnt_bits,offsetlsb), UFix(0, log2up(databits))).toUFix
rdy := !io.cpu.itlb_miss && (state === s_ready) && (!r_cpu_req_val || tag_hit);
io.cpu.resp_data := data_mux.io.out
io.mem.req_val := (state === s_request);
io.mem.req_addr := r_cpu_miss_addr(tagmsb,indexlsb).toUFix

2
rocket/src/main/scala/top.scala
View File

@ -15,7 +15,7 @@ class Top() extends Component {
val io = new ioTop();
val cpu = new rocketProc();
val icache = new rocketICacheDM(128); // # 64 byte cache lines
val icache = new rocketICache(128, 2); // 128 sets x 2 ways
val icache_pf = new rocketIPrefetcher();
val dcache = new HellaCacheDM(128);
val arbiter = new rocketMemArbiter();

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

@ -16,6 +16,11 @@ object log2up
def apply(in: Int) = if (in == 1) 1 else ceil(log(in)/log(2)).toInt
}
object ispow2
{
def apply(in: Int) = in > 0 && ((in & (in-1)) == 0)
}
object FillInterleaved
{
def apply(n: Int, in: Bits) =
@ -58,7 +63,7 @@ object UFixToOH
object LFSR16
{
def apply(increment: Bool) =
def apply(increment: Bool = Bool(true)) =
{
val width = 16
val lfsr = Reg(resetVal = UFix(1, width))