From 927d03ebbe36c2dcd8a0d1554f113390ffe314f9 Mon Sep 17 00:00:00 2001
From: Peter Evans <pevans@activecampaign.com>
Date: Fri, 29 Dec 2017 15:31:05 -0600
Subject: [PATCH] Add scan function (rename original scan -> opcode); test

---
 include/mos6502.dis.h |  3 ++-
 src/mos6502.dis.c     | 24 +++++++++++++++++-------
 tests/mos6502.dis.c   | 25 +++++++++++++++++++++++--
 3 files changed, 42 insertions(+), 10 deletions(-)

diff --git a/include/mos6502.dis.h b/include/mos6502.dis.h
index a9fce07..98d2561 100644
--- a/include/mos6502.dis.h
+++ b/include/mos6502.dis.h
@@ -5,8 +5,9 @@
 #include "vm_segment.h"
 
 extern int mos6502_dis_expected_bytes(vm_8bit);
-extern int mos6502_dis_scan(FILE *, vm_segment *, int);
+extern int mos6502_dis_opcode(FILE *, vm_segment *, int);
 extern void mos6502_dis_instruction(FILE *, int);
 extern void mos6502_dis_operand(FILE *, int, vm_16bit);
+extern void mos6502_dis_scan(FILE *, vm_segment *, int, int);
 
 #endif
diff --git a/src/mos6502.dis.c b/src/mos6502.dis.c
index 86cf2c0..3c956b2 100644
--- a/src/mos6502.dis.c
+++ b/src/mos6502.dis.c
@@ -186,7 +186,7 @@ mos6502_dis_expected_bytes(int addr_mode)
  * of bytes consumed by scanning past the opcode and/or operand.
  */
 int
-mos6502_dis_scan(FILE *stream, vm_segment *segment, int address)
+mos6502_dis_opcode(FILE *stream, vm_segment *segment, int address)
 {
     vm_8bit opcode;
     vm_16bit operand;
@@ -240,13 +240,15 @@ mos6502_dis_scan(FILE *stream, vm_segment *segment, int address)
     // Print out the instruction code that our opcode represents.
     mos6502_dis_instruction(stream, mos6502_instruction(opcode));
 
-    // Let's "tab" over; each instruction code is 3 characters, so let's
-    // move over 5 spaces (4 spaces indent + 1, just to keep everything
-    // aligned by 4-character boundaries).
-    fprintf(stream, "     ");
+    if (expected) {
+        // Let's "tab" over; each instruction code is 3 characters, so let's
+        // move over 5 spaces (4 spaces indent + 1, just to keep everything
+        // aligned by 4-character boundaries).
+        fprintf(stream, "     ");
 
-    // Print out the operand given the proper address mode.
-    mos6502_dis_operand(stream, mos6502_addr_mode(opcode), operand);
+        // Print out the operand given the proper address mode.
+        mos6502_dis_operand(stream, mos6502_addr_mode(opcode), operand);
+    }
 
     // And let's terminate the line.
     fprintf(stream, "\n");
@@ -256,3 +258,11 @@ mos6502_dis_scan(FILE *stream, vm_segment *segment, int address)
     // opcode sequence would consume.
     return expected + 1;
 }
+
+void
+mos6502_dis_scan(FILE *stream, vm_segment *segment, int pos, int end)
+{
+    while (pos < end) {
+        pos += mos6502_dis_opcode(stream, segment, pos);
+    }
+}
diff --git a/tests/mos6502.dis.c b/tests/mos6502.dis.c
index 4601805..33e3801 100644
--- a/tests/mos6502.dis.c
+++ b/tests/mos6502.dis.c
@@ -164,7 +164,7 @@ Test(mos6502_dis, expected_bytes)
     TEST_BYTES(ZPY, 1);
 }
 
-Test(mos6502_dis, scan)
+Test(mos6502_dis, opcode)
 {
     vm_segment *segment;
     int bytes;
@@ -174,7 +174,28 @@ Test(mos6502_dis, scan)
     vm_segment_set(segment, 0, 0x29);   // AND (imm)
     vm_segment_set(segment, 1, 0x38);
 
-    bytes = mos6502_dis_scan(stream, segment, 0);
+    bytes = mos6502_dis_opcode(stream, segment, 0);
     assert_buf("    AND     #$38\n");
     cr_assert_eq(bytes, 2);
 }
+
+Test(mos6502_dis, scan)
+{
+    vm_segment *segment;
+
+    segment = vm_segment_create(1000);
+
+    vm_segment_set(segment, 0, 0x29);   // AND (imm)
+    vm_segment_set(segment, 1, 0x38);
+    vm_segment_set(segment, 2, 0x88);   // DEY (imp)
+    vm_segment_set(segment, 3, 0x6C);   // JMP (ind)
+    vm_segment_set(segment, 4, 0x12);
+    vm_segment_set(segment, 5, 0x34);
+
+    mos6502_dis_scan(stream, segment, 0, 6);
+
+    assert_buf("    AND     #$38\n"
+               "    DEY\n"
+               "    JMP     ($1234)\n"
+               );
+}