Implement JMP

and get rid of arbitrary run limitation.

4 files changed, 21 insertions, 4 deletions

diff --git a/eater_cpu/cpp/Veater_computer__main.cpp b/eater_cpu/cpp/Veater_computer__main.cpp
index 4de8454..b4cd413 100644
--- a/eater_cpu/cpp/Veater_computer__main.cpp
+++ b/eater_cpu/cpp/Veater_computer__main.cpp
@@ -33,6 +33,8 @@ void load_program(const std::unique_ptr<Veater_computer> &topp) {
        0x54,
        // NOP
        0x00,
+       // JMP -> @0
+       0x60,
        // HALT
        0xf0};
   std::copy(instructions.begin(), instructions.end(),
@@ -84,10 +86,6 @@ int main(int argc, char **argv, char **) {
     contextp->timeInc(1);
 
     topp->clk_in = !topp->clk_in;
-
-    if (topp->eater_computer->PC_out == 6 &&
-        topp->eater_computer->decoder__DOT__internal_state == 0x01)
-      break;
   }
   contextp->timeInc(10);
   tfp->dump(contextp->time());
diff --git a/eater_cpu/eater_decoder.sv b/eater_cpu/eater_decoder.sv
index 20e3e0b..f6a73e6 100644
--- a/eater_cpu/eater_decoder.sv
+++ b/eater_cpu/eater_decoder.sv
@@ -31,6 +31,7 @@ function CpuState insdep_state;
     SUB: insdep_state = SUB_INS_to_MAR;
     STA: insdep_state = STA_INS_to_MAR;
     LDI: insdep_state = LDI_INS_to_A;
+    JMP: insdep_state = JMP_INS_to_PC;
     OUT: insdep_state = OUT_A_to_OUT;
     HALT_op: insdep_state = HALT_st;
 
@@ -68,6 +69,9 @@ always @(posedge clk_i) begin
 
     LDI_INS_to_A: next_state = PC_to_MAR;
 
+    JMP_INS_to_PC: next_state = JMP_NOP;
+    JMP_NOP: next_state = PC_to_MAR;
+
     OUT_A_to_OUT: next_state = PC_to_MAR;
 
     HALT_st: next_state = HALT_st;
@@ -161,6 +165,14 @@ always_comb begin
         internal_flags.A_in = 1;
     end
 
+    JMP_INS_to_PC: begin
+        internal_flags.INS_out = 1;
+        internal_flags.PC_in = 1;
+    end
+
+    JMP_NOP: begin
+    end
+
     OUT_A_to_OUT: begin
         internal_flags.A_out = 1;
         internal_flags.OUT_in = 1;
diff --git a/eater_cpu/eater_types.sv b/eater_cpu/eater_types.sv
index 43e3a0d..14c7736 100644
--- a/eater_cpu/eater_types.sv
+++ b/eater_cpu/eater_types.sv
@@ -47,6 +47,11 @@ typedef enum logic[7:0] {
     // LDI: a) LSB of INStruction into A
     LDI_INS_to_A,
 
+    // JMP: a) Put 4 LSB of INS -> PC
+    JMP_INS_to_PC,
+    // JMP: b) Needed??? Wait for value to be clocked in to be actually used
+    JMP_NOP,
+
     // OUT: A -> OUT
     OUT_A_to_OUT,
 
@@ -61,6 +66,7 @@ typedef enum logic[3:0] {
     SUB = 'b0011,
     STA = 'b0100,
     LDI = 'b0101,
+    JMP = 'b0110,
     OUT = 'b1110,
     HALT_op = 'b1111
 } eater_instruction;
diff --git a/eater_cpu/readme.txt b/eater_cpu/readme.txt
index 57c65ef..e4b28cd 100644
--- a/eater_cpu/readme.txt
+++ b/eater_cpu/readme.txt
@@ -34,6 +34,7 @@ ADD <memaddress>  0b_0010_<memaddress>    "Add memory": mem>B, A + B -> A
 SUB <memaddress>  0b_0011_<memaddress>    "Sub memory": mem>B, A - B-> A
 STA <memaddress>  0b_0100_<memaddress>    Store A -> memory
 LDI <value>       0b_0101_<value>         Store <value> -> A
+JMP <address>     0b_0110_<address>       <address> -> PC
 OUT ____________  0b_1110_xxxx            Output A -> OUT
 HLT ____________  0b_1111_xxxx            Sets halt flag
 ---