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Optimize CSR immediate handling

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This commit is contained in:
Olof Kindgren 2020-02-19 10:02:48 +01:00
parent badcd7ea55
commit 7f16f17ca5
3 changed files with 7 additions and 7 deletions
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4
rtl/serv_decode.v
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@ -52,6 +52,7 @@ module serv_decode
output wire o_csr_mcause_en,
output wire [1:0] o_csr_source,
output wire o_csr_d_sel,
output wire o_csr_imm,
//To top
output wire o_imm,
output wire o_op_b_source,
@ -151,6 +152,7 @@ module serv_decode
assign o_csr_source = funct3[1:0];
assign o_csr_d_sel = funct3[2];
assign o_csr_imm = o_rf_rs1_addr[0];
assign o_csr_addr = (op26 & !op20) ? CSR_MSCRATCH :
(op26 & !op21) ? CSR_MEPC :
@ -209,6 +211,8 @@ module serv_decode
imm30_25 <= {m2[1] ? imm7 : m2[0] ? signbit : imm19_12_20[0], imm30_25[5:1]};
imm24_20 <= {imm30_25[0], imm24_20[4:1]};
imm11_7 <= {imm30_25[0], imm11_7[4:1]};
if (csr_op & o_csr_d_sel)
o_rf_rs1_addr <= {1'b0,o_rf_rs1_addr[4:1]};
end
end

5
rtl/serv_state.v
View file

@ -18,7 +18,6 @@ module serv_state
input wire i_slt_op,
input wire i_e_op,
input wire i_rd_op,
input wire [4:0] i_rs1_addr,
output wire o_init,
output wire o_cnt_en,
output reg [4:0] o_cnt,
@ -33,8 +32,7 @@ module serv_state
output wire [1:0] o_mem_bytecnt,
input wire i_mem_misalign,
output reg o_cnt_done,
output wire o_bufreg_hold,
output wire o_csr_imm);
output wire o_bufreg_hold);
localparam [1:0]
IDLE = 2'd0,
@ -49,7 +47,6 @@ module serv_state
//Update PC in RUN or TRAP states
assign o_ctrl_pc_en = o_cnt_en & !o_init;
assign o_csr_imm = (o_cnt < 5) ? i_rs1_addr[o_cnt[2:0]] : 1'b0;
assign o_alu_shamt_en = (o_cnt < 5) & o_init;
assign o_mem_bytecnt = o_cnt[4:3];

5
rtl/serv_top.v
View file

@ -163,7 +163,6 @@ module serv_top
.i_slt_op (slt_op),
.i_e_op (e_op),
.i_rd_op (rd_op),
.i_rs1_addr (rs1_addr),
.o_init (init),
.o_cnt_en (cnt_en),
.o_cnt (cnt),
@ -178,8 +177,7 @@ module serv_top
.i_alu_sh_done (alu_sh_done),
.o_dbus_cyc (o_dbus_cyc),
.o_mem_bytecnt (mem_bytecnt),
.i_mem_misalign (mem_misalign),
.o_csr_imm (csr_imm));
.i_mem_misalign (mem_misalign));
wire bufreg_clr_lsb;
@ -237,6 +235,7 @@ module serv_top
.o_csr_mcause_en (csr_mcause_en),
.o_csr_source (csr_source),
.o_csr_d_sel (csr_d_sel),
.o_csr_imm (csr_imm),
//To top
.o_imm (imm),
.o_rd_csr_en (rd_csr_en),