From 601835e33298015cf49f0ab33a7ef3d61b003ad9 Mon Sep 17 00:00:00 2001 From: Alejandro Soto Date: Sat, 24 Sep 2022 21:41:46 -0600 Subject: Implement initial decoder --- rtl/core/decode/conds.sv | 39 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 39 insertions(+) create mode 100644 rtl/core/decode/conds.sv (limited to 'rtl/core/decode/conds.sv') diff --git a/rtl/core/decode/conds.sv b/rtl/core/decode/conds.sv new file mode 100644 index 0000000..3eef925 --- /dev/null +++ b/rtl/core/decode/conds.sv @@ -0,0 +1,39 @@ +`include "core/isa.sv" +`include "core/psr.sv" + +module core_decode_conds +( + input logic[3:0] cond, + input psr_flags flags, + output logic execute, + undefined +); + + always_comb begin + undefined = 0; + + unique case(cond) + `COND_EQ: execute = flags.z; + `COND_NE: execute = ~flags.z; + `COND_HS: execute = flags.c; + `COND_LO: execute = ~flags.c; + `COND_MI: execute = flags.n; + `COND_PL: execute = ~flags.n; + `COND_VS: execute = flags.v; + `COND_VC: execute = ~flags.v; + `COND_HI: execute = flags.c & ~flags.z; + `COND_LS: execute = ~flags.c | flags.z; + `COND_GE: execute = flags.n ~^ flags.v; + `COND_LT: execute = flags.n ^ flags.v; + `COND_GT: execute = ~flags.z & (flags.n ~^ flags.v); + `COND_LE: execute = flags.z | (flags.n ^ flags.v); + `COND_AL: execute = 1; + + `COND_UD: begin + execute = 1'bx; + undefined = 1; + end + endcase + end + +endmodule -- cgit v1.2.3