Miroirs/hp-saturn
1
0
Fork 0
mirror of https://github.com/sxpert/hp-saturn synced 2024-11-16 19:50:19 +01:00
Code Issues Projects Releases Packages Wiki Activity Actions

move to using the ALU

Browse source
This commit is contained in:
Raphael Jacquot 2019-02-11 09:12:19 +01:00
parent 9cd9c18381
commit 0eeb018b56
1 changed files with 25 additions and 12 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

37
opcodes/Dx_regs_field_A.v
View file

@ -8,20 +8,33 @@
`include "decstates.v"
`DEC_DX: begin
case (nb_in)
4'hA: begin
A[19:0] <= C[19:0];
$display("%5h A=C\tA", inst_start_PC);
field <= `T_FIELD_A;
alu_first <= 0;
alu_last <= 4;
case (nb_in[3:2])
2'b00: begin
alu_op <= `ALU_OP_ZERO;
alu_reg_dest <= {2'b00, nb_in[1:0]};
end
4'hE: begin
A[19:0] <= C[19:0];
C[19:0] <= A[19:0];
$display("%5h ACEX\tA", inst_start_PC);
2'b01: begin
alu_op <= `ALU_OP_COPY;
alu_reg_dest <= {2'b00, nb_in[1:0]};
alu_reg_src1 <= {2'b00, nb_in[0], !(nb_in[1] | nb_in[0])};
end
default: begin
$display("ERROR : DEC_DX");
decode_error <= 1;
2'b10: begin
alu_op <= `ALU_OP_COPY;
alu_reg_dest <= {2'b00, nb_in[0], !(nb_in[1] | nb_in[0])};
alu_reg_src1 <= {2'b00, nb_in[1:0]};
end
2'b11: begin
alu_op <= `ALU_OP_EXCH;
alu_reg_dest <= {2'b00, nb_in[1] & nb_in[0], (!nb_in[1]) & nb_in[0]};
alu_reg_src1 <= {2'b00, nb_in[1] | nb_in[0], (!nb_in[1]) ^ nb_in[0]};
end
endcase
decstate <= `DEC_START;
alu_debug <= 1;
next_cycle <= `BUSCMD_NOP;
decstate <= `DEC_ALU_INIT;
alu_return <= `DEC_START;
end