From 6b16bd1b8ef0031a79d39ebe6eb0483265c8dd2d Mon Sep 17 00:00:00 2001
From: Nunuhara Cabbage <nunuhara@haniwa.technology>
Date: Sat, 21 Dec 2019 07:19:38 -0800
Subject: [PATCH] Implement A_REVERSE instruction

---
 instructions.c |  4 ++--
 page.c         | 12 ++++++++++++
 page.h         |  1 +
 vm.c           |  6 ++++++
 4 files changed, 21 insertions(+), 2 deletions(-)

diff --git a/instructions.c b/instructions.c
index 77026c5..aa69c37 100644
--- a/instructions.c
+++ b/instructions.c
@@ -221,8 +221,8 @@ const struct instruction instructions[NR_OPCODES] = {
         OP(LI_RSHIFTA, 0),
         OP(LI_INC, 0),
         OP(LI_DEC, 0),
-        OP(A_FIND, 0), // TODO
-        OP(A_REVERSE, 0), // TODO
+        OP(A_FIND, 0),
+        OP(A_REVERSE, 0),
         OP(SH_SR_ASSIGN, 0), // TODO
         OP(SH_MEM_ASSIGN_LOCAL, 0), // TODO
         OP(A_NUMOF_GLOB_1, 0), // TODO
diff --git a/page.c b/page.c
index 3917fe9..8863732 100644
--- a/page.c
+++ b/page.c
@@ -488,3 +488,15 @@ int array_find(struct page *page, int start, int end, union vm_value v, int comp
 	}
 	return -1;
 }
+
+void array_reverse(struct page *page)
+{
+	if (!page)
+		return;
+
+	for (int start = 0, end = page->nr_vars-1; start < end; start++, end--) {
+		union vm_value tmp = page->values[start];
+		page->values[start] = page->values[end];
+		page->values[end] = tmp;
+	}
+}
diff --git a/page.h b/page.h
index cc761f3..474c803 100644
--- a/page.h
+++ b/page.h
@@ -100,5 +100,6 @@ bool array_erase(struct page **page, int i);
 void array_insert(struct page **_page, int i, union vm_value v, int data_type, int struct_type);
 void array_sort(struct page *page, int compare_fno);
 int array_find(struct page *page, int start, int end, union vm_value v, int compare_fno);
+void array_reverse(struct page *page);
 
 #endif /* SYSTEM4_PAGE_H */
diff --git a/vm.c b/vm.c
index 36f2150..ad0fb0a 100644
--- a/vm.c
+++ b/vm.c
@@ -1556,6 +1556,12 @@ static void execute_instruction(enum opcode opcode)
 		int start = stack_pop().i;
 		int array = stack_pop_var()->i;
 		stack_push(array_find(heap[array].page, start, end, v, fno));
+		break;
+	}
+	case A_REVERSE: {
+		int array = stack_pop_var()->i;
+		array_reverse(heap[array].page);
+		break;
 	}
 	// -- NOOPs ---
 	case FUNC: