From ee433509972d9390a52f188e902eb74e55596822 Mon Sep 17 00:00:00 2001 From: bd Date: Mon, 14 Apr 2025 16:28:05 -0400 Subject: Allow multi-level cache by passing a size into the constructor --- inc/cache.h | 56 ++++++++++++++++++++++++++++++------------------------ inc/definitions.h | 31 ------------------------------ inc/dram.h | 9 +++++++++ src/cache.cc | 24 +++++++++-------------- src/dram.cc | 1 - tests/c11.h | 11 +++++++++-- tests/cache_2_1.cc | 21 ++++++++++++++++++++ 7 files changed, 79 insertions(+), 74 deletions(-) create mode 100644 tests/cache_2_1.cc diff --git a/inc/cache.h b/inc/cache.h index 0f15536..325d46f 100644 --- a/inc/cache.h +++ b/inc/cache.h @@ -3,40 +3,45 @@ #include "definitions.h" #include "storage.h" #include +#include #include #include +/** + * Parse an address into a tag, index into the cache table, and a line + * offset. + * @param the address to be parsed + * @param the resulting tag + * @param the resulting index + * @param the resulting offset + */ +// clang-format off +#define GET_FIELDS(a, t, i, o) \ + *(t) = GET_MID_BITS(a, this->size + LINE_SPEC, MEM_WORD_SPEC); \ + *(i) = GET_MID_BITS(a, LINE_SPEC, this->size + LINE_SPEC); \ + *(o) = GET_LS_BITS(a, LINE_SPEC) +// clang-format on + class Cache : public Storage { public: /** - * Constructor. +nn * Constructor. * @param The number of `lines` contained in memory. The total number of * words is this number multiplied by LINE_SIZE. * @param The next lowest level in storage. Methods from this object are * called in case of a cache miss. + * @param The number of bits required to specify a line in this level of cache. * @param The number of clock cycles each access takes. * @return A new cache object. */ - Cache(Storage *lower, int delay); + Cache(Storage *lower, unsigned int size, int delay); ~Cache(); - int - write_word(void *, signed int, int) override; - int - write_line(void *, std::array, int) override; - int - read_line(void *, int, std::array &) override; - int - read_word(void *, int, signed int &) override; - - /** - * Getter for the meta attribute. - * TODO this doesn't seem like good object-oriented practice. - * @return this->meta - */ - std::array, L1_CACHE_LINES> - get_meta() const; + int write_word(void *, signed int, int) override; + int write_line(void *, std::array, int) override; + int read_line(void *, int, std::array &) override; + int read_word(void *, int, signed int &) override; private: /** @@ -47,8 +52,7 @@ class Cache : public Storage * @param the address to write to * @param the function to call when an access should be completed */ - int - process(void *id, int address, std::function request_handler); + int process(void *id, int address, std::function request_handler); /** * Returns OK if `id` is allowed to complete its request this cycle. * Handles cache misses, wait times, and setting the current id this @@ -56,8 +60,7 @@ class Cache : public Storage * @param the id asking for a resource * @return 1 if the access can be carried out this function call, 0 otherwise. */ - int - is_access_cleared(void *id, int address); + int is_access_cleared(void *id, int address); /** * Helper for is_access_cleared. * Fetches `address` from a lower level of storage if it is not already @@ -65,15 +68,18 @@ class Cache : public Storage * @param the address that must be present in cache. * @param 0 if the address is currently in cache, 1 if it is being fetched. */ - int - is_address_missing(int address); + int is_address_missing(int address); + /** + * The number of bits required to specify a line in this level of cache. + */ + unsigned int size; /** * An array of metadata about elements in `data`. * If the first value of an element is negative, the corresponding * element in `data` is invalid. If the most second value of an element * is nonzero, the corresponding element in `data` is dirty. */ - std::array, L1_CACHE_LINES> meta; + std::vector> meta; }; #endif /* CACHE_H_INCLUDED */ diff --git a/inc/definitions.h b/inc/definitions.h index 113c6e4..db43426 100644 --- a/inc/definitions.h +++ b/inc/definitions.h @@ -25,15 +25,6 @@ #define MEM_WORDS static_cast(pow(2, MEM_WORD_SPEC)) #define MEM_LINES static_cast(pow(2, MEM_LINE_SPEC)) -/** - * The number of bits to specify a l1 cache word - * The number of bits to specify a l1 cache line - * The total number of lines in l1 cache - */ -#define L1_CACHE_WORD_SPEC 7 -#define L1_CACHE_LINE_SPEC static_cast(L1_CACHE_WORD_SPEC - LINE_SPEC) -#define L1_CACHE_LINES static_cast(pow(2, L1_CACHE_LINE_SPEC)) - /** * The total number of cycles a memory access takes */ @@ -61,26 +52,4 @@ */ #define GET_MID_BITS(k, m, n) GET_LS_BITS((k) >> (m), ((n) - (m))) -/** - * Parse an address into a tag, index into the cache table, and a line - * offset. - * @param the address to be parsed - * @param the resulting tag - * @param the resulting index - * @param the resulting offset - */ -// clang-format off -#define GET_FIELDS(a, t, i, o) \ - *(t) = GET_MID_BITS(a, L1_CACHE_LINE_SPEC + LINE_SPEC, MEM_WORD_SPEC); \ - *(i) = GET_MID_BITS(a, LINE_SPEC, L1_CACHE_LINE_SPEC + LINE_SPEC); \ - *(o) = GET_LS_BITS(a, LINE_SPEC) - -/** - * Ensures address is within the current memory size using a clean wrap. - * @param an address - */ -#define WRAP_ADDRESS(a) \ - ((a < 0) ? ((a % MEM_WORDS) + MEM_WORDS) % MEM_WORDS : a % MEM_WORDS) -// clang-format on - #endif /* DEFINITIONS_H_INCLUDED */ diff --git a/inc/dram.h b/inc/dram.h index 140cbb1..fc46b47 100644 --- a/inc/dram.h +++ b/inc/dram.h @@ -5,6 +5,15 @@ #include #include +// clang-format off +/** + * Ensures address is within the current memory size using a clean wrap. + * @param an address + */ +#define WRAP_ADDRESS(a) \ + ((a < 0) ? ((a % MEM_WORDS) + MEM_WORDS) % MEM_WORDS : a % MEM_WORDS) +// clang-format on + class Dram : public Storage { public: diff --git a/src/cache.cc b/src/cache.cc index acbabcf..307d6d0 100644 --- a/src/cache.cc +++ b/src/cache.cc @@ -1,13 +1,17 @@ #include "cache.h" #include "definitions.h" -#include +#include #include -Cache::Cache(Storage *lower, int delay) : Storage(delay) +Cache::Cache(Storage *lower, unsigned int size, int delay) : Storage(delay) { - this->data->resize(L1_CACHE_LINES); + int true_size; + + true_size = 1 << size; + this->data->resize(true_size); + this->meta = std::vector>(true_size, {-1, -1}); + this->size = size; this->lower = lower; - this->meta.fill({-1, -1}); } Cache::~Cache() @@ -35,7 +39,6 @@ Cache::write_line(void *id, std::array data_line, int add }); } -// TODO: tests for multi level cache int Cache::read_line(void *id, int address, std::array &data_line) { @@ -103,8 +106,7 @@ Cache::is_address_missing(int expected) r = 1; if (meta->at(1) >= 0) { q = this->lower->write_line( - this, *actual, - ((index << LINE_SPEC) + (meta->at(0) << (L1_CACHE_LINE_SPEC + LINE_SPEC)))); + this, *actual, ((index << LINE_SPEC) + (meta->at(0) << (this->size + LINE_SPEC)))); if (q) { meta->at(1) = -1; } @@ -118,11 +120,3 @@ Cache::is_address_missing(int expected) return r; } - -std::array, L1_CACHE_LINES> -Cache::get_meta() const -{ - std::array, L1_CACHE_LINES> ret; - std::copy(std::begin(this->meta), std::end(this->meta), std::begin(ret)); - return ret; -} diff --git a/src/dram.cc b/src/dram.cc index 2fd8a91..18c1a3e 100644 --- a/src/dram.cc +++ b/src/dram.cc @@ -24,7 +24,6 @@ Dram::write_word(void *id, signed int data, int address) return process(id, address, [&](int line, int word) { this->data->at(line).at(word) = data; }); } -// TODO requires testing int Dram::read_line(void *id, int address, std::array &data_line) { diff --git a/tests/c11.h b/tests/c11.h index eb59cc0..6d63c77 100644 --- a/tests/c11.h +++ b/tests/c11.h @@ -6,12 +6,19 @@ #include #include +/** + * one way associative, single level + */ class C11 { public: - C11() : m_delay(4), c_delay(2), mem(new int), fetch(new int) + C11() { - this->c = new Cache(new Dram(this->m_delay), this->c_delay); + this->m_delay = 4; + this->c_delay = 2; + this->mem = new int(); + this->fetch = new int(); + this->c = new Cache(new Dram(this->m_delay), 5, this->c_delay); this->expected = {0, 0, 0, 0}; this->actual = this->c->view(0, 1)[0]; } diff --git a/tests/cache_2_1.cc b/tests/cache_2_1.cc new file mode 100644 index 0000000..101c6c3 --- /dev/null +++ b/tests/cache_2_1.cc @@ -0,0 +1,21 @@ +#include "c11.h" +#include "cache.h" +#include "dram.h" +#include "storage.h" +#include + +/** + * one way associative, two level + */ +class C21 : public C11 +{ + public: + C21() : C11() + { + Storage *s; + + s = new Dram(this->m_delay); + s = new Cache(s, 5, this->c_delay); + this->c = new Cache(s, 7, this->c_delay); + } +}; -- cgit v1.2.3