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 private Queue<Long> toDispatch = new LinkedList<Long>();
98 public void service() {
100 if (toDispatch.size() > 0) {
101 //if (!box_out.readyForDataFromShip()) return;
102 //box_out.addDataFromShip(toDispatch.remove());
103 getInterpreter().dispatch(getInterpreter().readInstruction(toDispatch.remove(), getDock("out")));
106 if (box_inCBD.dataReadyForShip() && box_out.readyForDataFromShip()) {
107 long val = box_inCBD.removeDataForShip();
108 long addr = val >> 6;
109 long size = val & 0x3f;
110 for(int i=0; i<size; i++)
111 toDispatch.add(readMem((int)(addr+i)));
115 if (box_inDataWrite.dataReadyForShip() && box_out.readyForDataFromShip()) {
116 writeMem((int)addr, box_inDataWrite.removeDataForShip());
117 box_out.addDataFromShip(0);
122 if (box_out.readyForDataFromShip()) {
123 box_out.addDataFromShip(readMem((int)addr));
129 } else if (box_inAddrRead.dataReadyForShip()) {
130 addr = box_inAddrRead.removeDataForShip();
135 } else if (box_inAddrWrite.dataReadyForShip()) {
136 addr = box_inAddrWrite.removeDataForShip();
143 == FleetSim ==============================================================
145 == FPGA ==============================================================
147 reg [(`CODEBAG_SIZE_BITS-1):0] cursor;
150 wire [(`BRAM_ADDR_WIDTH-1):0] addr1;
151 wire [(`BRAM_ADDR_WIDTH-1):0] addr2;
152 wire [(`BRAM_DATA_WIDTH-1):0] val2;
153 assign addr1 = write_flag ? inAddrWrite_d[(`DATAWIDTH-1):0] : inAddrRead_d[(`DATAWIDTH-1):0];
154 assign addr2 = (inCBD_d[(`INSTRUCTION_WIDTH-1):(`CODEBAG_SIZE_BITS)])+cursor;
156 bram14 mybram(clk, rst, write_flag, addr1, addr2, inDataWrite_d, out_d_, val2);
158 always @(posedge clk) begin
168 if (!inAddrRead_r && inAddrRead_a) inAddrRead_a <= 0;
169 if (!inDataWrite_r && inDataWrite_a) inDataWrite_a <= 0;
170 if (!inAddrWrite_r && inAddrWrite_a) inAddrWrite_a <= 0;
172 if ( out_r && !out_a) begin
173 end else if ( out_r && out_a) begin out_r <= 0;
174 end else if (!out_r && !out_a && inAddrRead_r && !inAddrRead_a) begin
178 end else if (!out_r && !out_a && inAddrWrite_r && inDataWrite_r) begin
179 // timing note: it's okay to set the *_a flags here because *_d will still
180 // be valid on the *next* cycle, which is all we care about
186 end else if ( outIhorn_r && outIhorn_a) begin outIhorn_r <= 0;
187 end else if (!inCBD_r && inCBD_a) begin inCBD_a <= 0;
188 end else if ( inCBD_r && !inCBD_a && !outIhorn_r && !outIhorn_a) begin
189 if (cursor < inCBD_d[(`CODEBAG_SIZE_BITS-1):0]) begin
192 cursor <= cursor + 1;
204 == Test ==============================================================
210 // ships required in order to run this code
212 #ship memory : Memory
214 // instructions not in any codebag are part of the "root codebag"
215 // which is dispatched when the code is loaded
229 == Constants ========================================================
231 == Contributors =========================================================
232 Adam Megacz <megacz@cs.berkeley.edu>