added: alu jumps

[calu.git] / cpu / src / alu_b.vhd

diff --git a/cpu/src/alu_b.vhd b/cpu/src/alu_b.vhd
index 340536561a4e7e9f407c9ba8b28be2afe2235f4f..8399d6087e835d11d1375fc5a43e4c7d5bf10c27 100755 (executable)
--- a/cpu/src/alu_b.vhd
+++ b/cpu/src/alu_b.vhd
@@ -46,21 +46,24 @@ calc: process(left_operand, right_operand,displacement, cond, op_group, op_detai
        variable res_prod : std_logic;\r
        variable cond_met : std_logic;\r
        variable mem_en : std_logic;
-        variable mem_op : std_logic;\r
+        variable mem_op : std_logic;
+       variable alu_jmp : std_logic;\r
 begin\r
        result_v := alu_state;\r
        \r
-       result_v.result := add_result.result;\r
        res_prod := '1';\r
        mem_en := '0';
-        mem_op := '0';\r
-        addr <= add_result.result;
+        mem_op := '0';
+       alu_jump := '0';\r
+  
         left <= left_operand;
         right <= right_operand;
 
         addr <= add_result.result;
         data <= right_operand;\r
-       \r
+       
+       result_v.result := add_result.result;
+\r
        case cond is\r
        when COND_NZERO =>\r
                cond_met := not(alu_state.status.zero);\r
@@ -96,7 +99,9 @@ begin
                cond_met := '0';\r
        when others => null;\r
        end case;\r
-       \r
+       
+       cond_met := cond_met and (alu_state.alu_jmp xnor alu_state.brpr);
+\r
        case op_group is\r
        when ADDSUB_OP =>\r
                result_v := add_result;\r
@@ -119,7 +124,13 @@ begin
                 if op_detail(ST_OPT) = '1' then
                         right <= displacement;
                         mem_en := '1';
-                end if;\r
+                end if;
+       when JMP_OP =>
+               if op_detail(JMP_REG_OPT) = '0' then
+                       left <= prog_cnt;
+               end if;
+               result_v.alu_jmp := '1';
+       when JMP_ST_OP => null;\r
        end case;\r
        \r
 \r
@@ -137,6 +148,7 @@ begin
        result_v.reg_op := not(op_detail(NO_DST_OPT)) and res_prod and cond_met;\r
        result_v.mem_en := mem_en and cond_met;
         result_v.mem_op := mem_op and cond_met;
+       result_v.alu_jmp := alu_jmp and cond_met;
         \r
        alu_result <= result_v;\r
        \r