add tee instruction

2 files changed, 6 insertions, 1 deletions

diff --git a/design/stack_machine.v b/design/stack_machine.v
index 1fddb18..d466cc8 100644
--- a/design/stack_machine.v
+++ b/design/stack_machine.v
@@ -127,6 +127,7 @@ module stack_machine
    assign extended_instruction_bits = instruction[8:0];
 
    /* extended instructions */
+   parameter INSTR_TEE = 9'd7;
    parameter INSTR_MUL = 9'd6;
    parameter INSTR_DIV = 9'd5;
    parameter INSTR_SUB = 9'd4;
@@ -326,6 +327,8 @@ module stack_machine
 		   end
 		   INSTR_MUL :
 		     r0 <= r0 * r1;
+		   INSTR_TEE :
+		     r1 <= r0;
 		   default : begin
 `ifdef SIMULATION
 		      $display("operation not implemented yet");
diff --git a/tclasm.tcl b/tclasm.tcl
index d326c00..99b01a1 100755
--- a/tclasm.tcl
+++ b/tclasm.tcl
@@ -181,6 +181,8 @@ proc __encode_extended_instruction {instruction} {
 	return [__to_binary 5 9]
     } elseif {"$instruction" == "mul"} {
 	return [__to_binary 6 9]
+    } elseif {"$instruction" == "tee"} {
+	return [__to_binary 7 9]
     } else {
 	error "no such extended instruction: '$instruction'"
     }
@@ -306,7 +308,7 @@ proc cond_jump {{address im_address}} {
     }
 }
 
-foreach instruction {halt nop swap add sub div mul} {
+foreach instruction {halt nop swap add sub div mul tee} {
     proc $instruction {} "
         _extended_instruction $instruction
     "