From 6b160c6ca26ba629a403ec907886f7f3b362d979 Mon Sep 17 00:00:00 2001
From: Peter Evans <pevans@activecampaign.com>
Date: Fri, 19 Jan 2018 12:18:24 -0600
Subject: [PATCH] Show the dereferenced value for a given address

---
 include/mos6502.h |  2 +-
 src/mos6502.c     |  6 +++---
 src/mos6502.dis.c | 24 ++++++++++++++++++++++--
 3 files changed, 26 insertions(+), 6 deletions(-)

diff --git a/include/mos6502.h b/include/mos6502.h
index dea1e71..a38e816 100644
--- a/include/mos6502.h
+++ b/include/mos6502.h
@@ -149,7 +149,7 @@ extern void mos6502_set_status(mos6502 *, vm_8bit);
  * Below are some functions that are defined in mos6502.addr.c
  */
 extern int mos6502_addr_mode(vm_8bit);
-extern mos6502_address_resolver mos6502_get_address_resolver(vm_8bit);
+extern mos6502_address_resolver mos6502_get_address_resolver(int);
 
 /*
  * All of our address modes
diff --git a/src/mos6502.c b/src/mos6502.c
index 64c5cf5..3a0839d 100644
--- a/src/mos6502.c
+++ b/src/mos6502.c
@@ -352,7 +352,7 @@ mos6502_execute(mos6502 *cpu)
 
     // First, we need to know how to resolve our effective address and
     // how to execute anything.
-    resolver = mos6502_get_address_resolver(opcode);
+    resolver = mos6502_get_address_resolver(mos6502_addr_mode(opcode));
     handler = mos6502_get_instruction_handler(opcode);
 
     // The operand is the effective operand, the value that the
@@ -454,9 +454,9 @@ mos6502_would_jump(int inst_code)
  * cpu) that an instruction will use.
  */
 mos6502_address_resolver
-mos6502_get_address_resolver(vm_8bit opcode)
+mos6502_get_address_resolver(int addr_mode)
 {
-    switch (mos6502_addr_mode(opcode)) {
+    switch (addr_mode) {
         case ACC: return mos6502_resolve_acc;
         case ABS: return mos6502_resolve_abs;
         case ABX: return mos6502_resolve_abx;
diff --git a/src/mos6502.dis.c b/src/mos6502.dis.c
index f57e19e..be94b03 100644
--- a/src/mos6502.dis.c
+++ b/src/mos6502.dis.c
@@ -12,6 +12,7 @@
 
 static char s_inst[4],
             s_oper[10],
+            s_value[3],
             s_label[13],
             s_state[51],
             s_bytes[12];
@@ -94,38 +95,53 @@ mos6502_dis_operand(mos6502 *cpu,
 {
     int rel_address;
     int ind_address;
+    vm_8bit eff_value;
+    mos6502_address_resolver resolv;
+
+    resolv = mos6502_get_address_resolver(addr_mode);
+    eff_value = resolv(cpu);
 
     switch (addr_mode) {
         case ACC:
             break;
         case ABS:
             snprintf(str, len, "$%04X", value);
+            snprintf(s_value, sizeof(s_value), "%02x", eff_value);
             break;
         case ABX:
             snprintf(str, len, "$%04X,X", value);
+            eff_value = resolv(cpu);
+            snprintf(s_value, sizeof(s_value), "%02x", eff_value);
             break;
         case ABY:
             snprintf(str, len, "$%04X,Y", value);
+            snprintf(s_value, sizeof(s_value), "%02x", eff_value);
             break;
         case IMM:
             snprintf(str, len, "#$%02X", value);
+            snprintf(s_value, sizeof(s_value), "%02x", eff_value);
             break;
         case IMP:
+            snprintf(s_value, sizeof(s_value), "%02X", 0);
             break;
         case IND:
             ind_address = mos6502_get(cpu, value + 1) << 8;
             ind_address |= mos6502_get(cpu, value);
             if (jump_table[ind_address]) {
                 mos6502_dis_label(str, len, ind_address);
+                snprintf(s_value, sizeof(s_value), "%02X", 0);
             } else {
                 snprintf(str, len, "($%04X)", value);
+                snprintf(s_value, sizeof(s_value), "%02x", eff_value);
             }
             break;
         case IDX:
             snprintf(str, len, "($%02X,X)", value);
+            snprintf(s_value, sizeof(s_value), "%02x", eff_value);
             break;
         case IDY:
             snprintf(str, len, "($%02X),Y", value);
+            snprintf(s_value, sizeof(s_value), "%02x", eff_value);
             break;
         case REL:
             rel_address = address + value;
@@ -134,17 +150,21 @@ mos6502_dis_operand(mos6502 *cpu,
             }
 
             mos6502_dis_label(str, len, rel_address);
+            snprintf(s_value, sizeof(s_value), "%02x", eff_value);
             break;
         case ZPG:
             // We add a couple of spaces here to help our output
             // comments line up.
             snprintf(str, len, "$%02X", value);
+            snprintf(s_value, sizeof(s_value), "%02x", eff_value);
             break;
         case ZPX:
             snprintf(str, len, "$%02X,X", value);
+            snprintf(s_value, sizeof(s_value), "%02x", eff_value);
             break;
         case ZPY:
             snprintf(str, len, "$%02X,Y", value);
+            snprintf(s_value, sizeof(s_value), "%02x", eff_value);
             break;
     }
 }
@@ -301,9 +321,9 @@ mos6502_dis_opcode(mos6502 *cpu, FILE *stream, int address)
         // what the PC was at the point of this opcode sequence; two,
         // the opcode;
         snprintf(s_state, sizeof(s_state) - 1, 
-                 "pc:%02x%02x cy:%02d val:%04x a:%02x x:%02x y:%02x p:%02x s:%02x", 
+                 "pc:%02x%02x cy:%02d val:%2s a:%02x x:%02x y:%02x p:%02x s:%02x", 
                 cpu->PC >> 8, cpu->PC & 0xff,
-                mos6502_cycles(cpu, opcode), operand,
+                mos6502_cycles(cpu, opcode), s_value,
                 cpu->A, cpu->X, cpu->Y, cpu->P, cpu->S);
 
         // And three, the operand, if any. Remembering that the operand