From f37a50d6cfe86e6f5ebe368c0868878fd72aa884 Mon Sep 17 00:00:00 2001
From: Wojciech Kosior <kwojtus@protonmail.com>
Date: Sat, 5 Sep 2020 18:32:44 +0200
Subject: add jump instruction together with bench

---
 Makefile                                     |  3 ++-
 design/stack_machine.v                       |  7 +++++++
 tclasm.tcl                                   |  9 +++++++++
 tests/stack_machine_jump/instructions.s.tcl  | 22 ++++++++++++++++++++++
 tests/stack_machine_jump/test.v              |  1 +
 tests/stack_machine_jump/words_to_verify.mem |  2 ++
 6 files changed, 43 insertions(+), 1 deletion(-)
 create mode 100755 tests/stack_machine_jump/instructions.s.tcl
 create mode 120000 tests/stack_machine_jump/test.v
 create mode 100644 tests/stack_machine_jump/words_to_verify.mem

diff --git a/Makefile b/Makefile
index 98631ef..454b499 100644
--- a/Makefile
+++ b/Makefile
@@ -41,7 +41,8 @@ STACK_MACHINE_TESTS := \
 	add \
 	sub \
 	div \
-	mul
+	mul \
+	jump
 
 # Add other tests here if You need
 TESTS := \
diff --git a/design/stack_machine.v b/design/stack_machine.v
index a6b2765..150f6c7 100644
--- a/design/stack_machine.v
+++ b/design/stack_machine.v
@@ -190,6 +190,10 @@ module stack_machine_new
    assign instr_set_sp = use_im && stack_same_size &&
 			 instruction[11:7] == 5'd0;
 
+   wire 	      instr_jump;
+   assign instr_jump = use_im && stack_same_size &&
+		       instruction[11:7] == 5'd1;
+
    /* Instructions, that grow stack */
    wire 	      instr_tee;
    assign instr_tee = !set_im && !use_im && stack_grows &&
@@ -493,6 +497,9 @@ module stack_machine_new
 	      if (instr_set_sp)
 		`SET_SP(im_effective);
 
+	      if (instr_jump)
+		`SET_PC(im_effective);
+
 	      /* Instructions, that grow stack */
 	      if (instr_tee)
 		r1 <= r1;
diff --git a/tclasm.tcl b/tclasm.tcl
index c5b1cb3..1f716ee 100644
--- a/tclasm.tcl
+++ b/tclasm.tcl
@@ -150,6 +150,15 @@ proc set_sp {address} {
 }
 
 
+proc _jump {address_part} {
+    puts 010000001[__to_binary $address_part 7]
+}
+
+proc jump {address} {
+    _with_im _jump $address
+}
+
+
 # Instructions, that grow stack
 
 proc tee {} {
diff --git a/tests/stack_machine_jump/instructions.s.tcl b/tests/stack_machine_jump/instructions.s.tcl
new file mode 100755
index 0000000..fe3b297
--- /dev/null
+++ b/tests/stack_machine_jump/instructions.s.tcl
@@ -0,0 +1,22 @@
+#!/usr/bin/env tclsh
+
+source tclasm.tcl
+
+## Let there be 2 pieces of code - each one storing a different value in memory
+## and halting afterwards. Jump instruction should cause the second piece of
+## code to execute instead of the first. We'll verify that by checking, which
+## value got written.
+
+## Ufortunately, our assembly currently doesn't compute label addresses for us.
+
+# Those 4 instructions should get encoded into 5 16-bit words, so they
+# will take 10 bytes total. Hence jump to address 10 is needed to skip them.
+jump 10
+const h12
+store h87C0
+halt
+
+# address 10 here
+const h34
+store h87C0
+halt
diff --git a/tests/stack_machine_jump/test.v b/tests/stack_machine_jump/test.v
new file mode 120000
index 0000000..f5b6a59
--- /dev/null
+++ b/tests/stack_machine_jump/test.v
@@ -0,0 +1 @@
+../stack_machine_store/test.v
\ No newline at end of file
diff --git a/tests/stack_machine_jump/words_to_verify.mem b/tests/stack_machine_jump/words_to_verify.mem
new file mode 100644
index 0000000..1b9f11d
--- /dev/null
+++ b/tests/stack_machine_jump/words_to_verify.mem
@@ -0,0 +1,2 @@
+// address  value
+   87C0     34
-- 
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