3 == Ports ===========================================================
14 == TeX ==============================================================
16 The {\tt Memory} ship represents an interface to a storage space,
17 which can be used to read from it or write to it. This storage space
18 might be a fast on-chip cache, off chip DRAM, or perhaps even a disk drive.
20 There may be multiple {\tt Memory} ships which interface to the same
21 physical storage space. An implementation of Fleet must provide
22 additional documentation to the programmer indicating which {\tt
23 Memory} ships correspond to which storage spaces. A single {\tt
24 Memory} ship may also access a ``virtual storage space'' formed by
25 concatenating multiple physical storage spaces.
27 \subsection*{Code Bag Fetch}
29 When a word appears at the {\tt inCBD} port, it is treated as a {\it
30 code bag descriptor}, as shown below:
33 \setlength{\bitwidth}{3mm}
36 \bitheader[b]{36,6,5,0}\\
43 When a word arrives at the {\tt inCBD} port, it is treated as a memory
44 read with {\tt inAddrRead=Address}, {\tt inStride=1}, and {\tt
49 When a word is delivered to {\tt inAddrRead}, the word residing in
50 memory at that address is provided at {\tt out}.
54 When a word is delivered to {\tt inAddrWrite} and {\tt inDataWrite},
55 the word at {\tt inDataWrite} is written to the address specified by
56 {\tt inAddrWrite}. Once the word is successfully committed to memory,
57 the value {\tt inAddr+inStride} is provided at {\tt out} (that is, the
58 address of the next word to be written).
62 Stride and count are not implemented.
64 We need a way to do an ``unordered fetch'' -- a way to tell the memory
65 unit to retrieve some block of words in any order it likes. This can
66 considerably accelerate fetches when the first word of the region is
67 not cached, but other parts are cached. This can also be used for
68 dispatching codebags efficiently -- but how will we make sure that
69 instructions destined for a given pump are dispatched in the correct
70 order (source sequence guarantee)?
72 A more advanced form would be ``unordered fetch of ordered records''
73 -- the ability to specify a record size (in words), the offset of the
74 first record, and the number of records to be fetched. The memory
75 unit would then fetch the records in any order it likes, but would be
76 sure to return the words comprising a record in the order in which
77 they appear in memory. This feature could be used to solve the source
78 sequence guarantee problem mentioned in the previous paragraph.
80 == Fleeterpreter ====================================================
81 private long[] mem = new long[0];
82 public long readMem(int addr) { return addr >= mem.length ? 0 : mem[addr]; }
83 public void writeMem(int addr, long val) {
84 if (addr >= mem.length) {
85 long[] newmem = new long[addr * 2 + 1];
86 System.arraycopy(mem, 0, newmem, 0, mem.length);
92 private long stride = 0;
93 private long count = 0;
94 private long addr = 0;
95 private boolean writing = false;
97 public void service() {
99 if (box_inCBD.dataReadyForShip()) {
100 long val = box_inCBD.removeDataForShip();
101 long addr = val >> 6;
102 long size = val & 0x3f;
103 dispatch((int)addr, (int)size);
108 if (box_inDataWrite.dataReadyForShip() && box_out.readyForDataFromShip()) {
109 writeMem((int)addr, box_inDataWrite.removeDataForShip());
110 box_out.addDataFromShip(0);
115 if (box_out.readyForDataFromShip()) {
116 box_out.addDataFromShip(readMem((int)addr));
122 } else if (box_inAddrRead.dataReadyForShip()) {
123 addr = box_inAddrRead.removeDataForShip();
128 } else if (box_inAddrWrite.dataReadyForShip()) {
129 // addr = box_inAddrWrite.peekPacketForShip().value;
130 box_inAddrWrite.removeDataForShip();
137 == FleetSim ==============================================================
139 == FPGA ==============================================================
141 reg [(`CODEBAG_SIZE_BITS-1):0] cursor;
144 wire [(`BRAM_ADDR_WIDTH-1):0] addr1;
145 wire [(`BRAM_ADDR_WIDTH-1):0] addr2;
146 wire [(`BRAM_DATA_WIDTH-1):0] val2;
147 assign addr1 = write_flag ? inAddrWrite_d[(`DATAWIDTH-1):0] : inAddrRead_d[(`DATAWIDTH-1):0];
148 assign addr2 = (inCBD_d[(`INSTRUCTION_WIDTH-1):(`CODEBAG_SIZE_BITS)])+cursor;
150 bram14 mybram(clk, rst, write_flag, addr1, addr2, inDataWrite_d, out_d_, val2);
152 always @(posedge clk) begin
162 if (!inAddrRead_r && inAddrRead_a) inAddrRead_a <= 0;
163 if (!inDataWrite_r && inDataWrite_a) inDataWrite_a <= 0;
164 if (!inAddrWrite_r && inAddrWrite_a) inAddrWrite_a <= 0;
166 if ( out_r && !out_a) begin
167 end else if ( out_r && out_a) begin out_r <= 0;
168 end else if (!out_r && !out_a && inAddrRead_r && !inAddrRead_a) begin
172 end else if (!out_r && !out_a && inAddrWrite_r && inDataWrite_r) begin
173 // timing note: it's okay to set the *_a flags here because *_d will still
174 // be valid on the *next* cycle, which is all we care about
180 end else if ( outIhorn_r && outIhorn_a) begin outIhorn_r <= 0;
181 end else if (!inCBD_r && inCBD_a) begin inCBD_a <= 0;
182 end else if ( inCBD_r && !inCBD_a && !outIhorn_r && !outIhorn_a) begin
183 if (cursor < inCBD_d[(`CODEBAG_SIZE_BITS-1):0]) begin
186 cursor <= cursor + 1;
198 == Test ==============================================================
204 // ships required in order to run this code
206 #ship memory : Memory
208 // instructions not in any codebag are part of the "root codebag"
209 // which is dispatched when the code is loaded
223 == Constants ========================================================
225 == Contributors =========================================================
226 Adam Megacz <megacz@cs.berkeley.edu>