M-extension support for SERV #60
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rtl/serv_bufreg.v
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| @@ -17,11 +19,13 @@ module serv_bufreg | |||
| input wire i_imm, | |||
| output wire o_q, | |||
| //External | |||
| output wire [31:0] o_dbus_adr); | |||
| output wire [31:0] o_dbus_adr, | |||
| output wire [31:0] o_mdu_rs1); | |||
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Rename o_mdu_rs1 to o_ext_rs1 instead since this can potentially be shared between different extensions
rtl/serv_decode.v
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| @@ -17,6 +18,8 @@ module serv_decode #( | |||
| output reg o_shift_op, | |||
| output reg o_slt_op, | |||
| output reg o_rd_op, | |||
| output reg o_mdu_op, | |||
| output reg [2:0] o_mdu_opcode, | |||
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Let's rename o_mdu_opcode to o_ext_funct3 to show what the value comes from and that the signal can be useful for multiple extensions
rtl/serv_mem_if.v
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| generate | ||
| if(MDU) begin | ||
| wire mdu_rd = i_mdu_op & (dat_valid ? dat_cur : signbit & i_signed); |
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I think that dat_valid will always be raised for MDU operations. Please check if we can simplify this expression to just i_mdu_op & dat_cur
rtl/serv_top.v
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| wire [4:0] rd_addr; | ||
| wire [4:0] rs1_addr; | ||
| wire [4:0] rs2_addr; | ||
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| wire [3:0] immdec_ctrl; | ||
| wire [3:0] immdec_en; | ||
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rtl/serv_top.v
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| @@ -386,7 +405,6 @@ module serv_top | |||
| .i_csr_rd (csr_rd), | |||
| .i_rd_csr_en (rd_csr_en), | |||
| .i_mem_rd (mem_rd), | |||
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serv.core
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| @@ -43,6 +44,11 @@ targets: | |||
| toplevel : serv_rf_top | |||
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| parameters: | |||
| MDU: | |||
| datatype : int | |||
| description: Enables RISC-V standard M-extension | |||
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Enables interface for RISC-V standard M-extension
servant.core
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| @@ -39,7 +39,7 @@ filesets: | |||
| - "!tool_quartus? (servant/servant_ram.v)" | |||
| - servant/servant.v | |||
| file_type : verilogSource | |||
| depend : [serv] | |||
| depend : {serv, mdu} | |||
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Use [ ] instead of { }. I actually didn't know it was allowed to use { }. Seems to work fine but made me a bit confused :)
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Thanks for reviewing, the code is modified according to the requested changes. |
servant.core
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| @@ -347,6 +347,7 @@ targets: | |||
| filesets : [soc, servant_tb] | |||
| parameters : | |||
| - RISCV_FORMAL | |||
| - MDU | |||
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This should also be "- mdu? (MDU=1)"
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Oh yes, this should be.
rtl/serv_rf_top.v
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| assign dbus_ack = i_dbus_ack; | ||
| end | ||
| assign o_ext_rs2 = o_dbus_dat; | ||
| endgenerate |
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I just realized that we need to move this generate block inside serv_top.v so that we can expose the extension interface for designs that uses serv_top directly instead of serv_rf_top (e.g. serving)
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Awesome! I have nothing more to complain about now. :) Well done and thank you for your contributions |
This project was the part of GSoC'21. Completed by @zeeshanrafique23 under the mentorship of @olofk.
The RTL of M-extension and changes made in serv are verified with RISC-V compliance tests. Follow the README to run the tests.
The parent repository of MDU can be found here: https://github.com/zeeshanrafique23/mdu.git
To run the serv with M-extension you have to add mdu in fusesoc core list, run this command to check the existing core:
and to add mdu as a fusesoc core run this command:
Now run this command to build the serv core with mdu:
Add
--vcdflag to generate.vcdfile to see the waveforms.For more details check this Blog.