hp-saturn/opcodes/80x.v
2019-02-10 12:04:53 +01:00

36 lines
802 B
Verilog

/******************************************************************************
* 80
* a lot of things start with 80...
*
*/
`include "decstates.v"
`include "bus_commands.v"
`DEC_80X: begin
case (nb_in)
4'h5: begin
add_out <= C[19:0];
next_cycle <= `BUSCMD_CONFIGURE;
decstate <= `DEC_START;
`ifdef SIM
$display("%05h CONFIG", inst_start_PC);
`endif
end
4'h8: decstate <= `DEC_808X;
4'hA: begin
next_cycle <= `BUSCMD_RESET;
decstate <= `DEC_START;
`ifdef SIM
$display("%05h RESET", inst_start_PC);
`endif
end
4'hC: decstate <= `DEC_C_EQ_P_N;
4'hD: decstate <= `DEC_P_EQ_C_N;
default: begin
$display("ERROR : DEC_80X");
decode_error <= 1;
end
endcase
end