From 1d604d774bdaecf70712ef2c484b0b1bc07e7d6a Mon Sep 17 00:00:00 2001
From: Ben Kurtovic <ben.kurtovic@gmail.com>
Date: Sun, 1 May 2016 03:48:33 -0500
Subject: [PATCH] Cleanup VDP debug code; don't enable IRQ until one instr past
 EI.

---
 src/vdp.c         | 26 +++++++++++---------------
 src/z80.c         | 10 +++++++---
 src/z80.h         |  1 +
 src/z80_ops.inc.c |  1 +
 4 files changed, 20 insertions(+), 18 deletions(-)

diff --git a/src/vdp.c b/src/vdp.c
index d8283b4..2baae00 100644
--- a/src/vdp.c
+++ b/src/vdp.c
@@ -415,24 +415,20 @@ void vdp_dump_registers(const VDP *vdp)
     return;
 
     DEBUG("Dumping PNT:")
-    for (uint16_t i = 0; i < 28 * 32; i += 32) {
-        uint16_t w[32];
-        for (uint8_t j = 0; j < 32; j++)
-            w[j] = vdp->vram[get_pnt_base(vdp) + 2 * (i + j)] +
-                  (vdp->vram[get_pnt_base(vdp) + 2 * (i + j) + 1] << 8);
-
-        DEBUG("- %03X %03X %03X %03X %03X %03X %03X %03X"
-               " %03X %03X %03X %03X %03X %03X %03X %03X"
-               " %03X %03X %03X %03X %03X %03X %03X %03X"
-               " %03X %03X %03X %03X %03X %03X %03X %03X",
-            w[0x00], w[0x01], w[0x02], w[0x03], w[0x04], w[0x05], w[0x06], w[0x07],
-            w[0x08], w[0x09], w[0x0A], w[0x0B], w[0x0C], w[0x0D], w[0x0E], w[0x0F],
-            w[0x10], w[0x11], w[0x12], w[0x13], w[0x14], w[0x15], w[0x16], w[0x17],
-            w[0x18], w[0x19], w[0x1A], w[0x1B], w[0x1C], w[0x1D], w[0x1E], w[0x1F])
+    for (uint16_t i = 0; i < 18; i++) {
+        uint16_t w[20];
+        for (uint8_t j = 0; j < 20; j++)
+            w[j] = get_background_tile(vdp, i + 3, j + 6);
+
+        DEBUG("- %03X %03X %03X %03X %03X %03X %03X %03X %03X %03X"
+               " %03X %03X %03X %03X %03X %03X %03X %03X %03X %03X",
+            w[0x00], w[0x01], w[0x02], w[0x03], w[0x04], w[0x05], w[0x06],
+            w[0x07], w[0x08], w[0x09], w[0x0A], w[0x0B], w[0x0C], w[0x0D],
+            w[0x0E], w[0x0F], w[0x10], w[0x11], w[0x12], w[0x13])
     }
 
     DEBUG("Dumping PGT:")
-    for (uint16_t i = 0; i < /* 512 */ 16; i++) {
+    for (uint16_t i = 0; i < /* 512 */ 32; i++) {
         uint32_t w[8];
         for (uint8_t j = 0; j < 8; j++)
             w[j] = vdp->vram[32 * i + 4 * j] +
diff --git a/src/z80.c b/src/z80.c
index 5d551fa..3bfc711 100644
--- a/src/z80.c
+++ b/src/z80.c
@@ -65,6 +65,7 @@ void z80_power(Z80 *z80)
 
     z80->except = false;
     z80->pending_cycles = 0;
+    z80->irq_wait = false;
 
     z80->trace.fresh = true;
     z80->trace.last_addr = 0;
@@ -231,7 +232,7 @@ static inline uint8_t get_interrupt_mode(const Z80 *z80)
 /*
     Handle an active IRQ line. Return the number of cycles consumed.
 */
-static inline uint8_t handle_interrupt(Z80 *z80)
+static inline uint8_t accept_interrupt(Z80 *z80)
 {
     TRACE("Z80 triggering mode-%d interrupt", get_interrupt_mode(z80))
     z80->regs.iff1 = z80->regs.iff2 = 0;
@@ -298,10 +299,13 @@ bool z80_do_cycles(Z80 *z80, double cycles)
 {
     cycles += z80->pending_cycles;
     while (cycles > 0 && !z80->except) {
-        if (io_check_irq(z80->io) && z80->regs.iff1) {
-            cycles -= handle_interrupt(z80);
+        if (io_check_irq(z80->io) && z80->regs.iff1 && !z80->irq_wait) {
+            cycles -= accept_interrupt(z80);
             continue;
         }
+        if (z80->irq_wait)
+            z80->irq_wait = false;
+
         uint8_t opcode = mmu_read_byte(z80->mmu, z80->regs.pc);
         increment_refresh_counter(z80);
         if (TRACE_LEVEL)
diff --git a/src/z80.h b/src/z80.h
index f08e911..4b7ee56 100644
--- a/src/z80.h
+++ b/src/z80.h
@@ -68,6 +68,7 @@ typedef struct {
     bool except;
     uint8_t exc_code, exc_data;
     double pending_cycles;
+    bool irq_wait;
     Z80TraceInfo trace;
 } Z80;
 
diff --git a/src/z80_ops.inc.c b/src/z80_ops.inc.c
index 3003872..198a3b5 100644
--- a/src/z80_ops.inc.c
+++ b/src/z80_ops.inc.c
@@ -1182,6 +1182,7 @@ static uint8_t z80_inst_ei(Z80 *z80, uint8_t opcode)
     (void) opcode;
     z80->regs.iff1 = true;
     z80->regs.iff2 = true;
+    z80->irq_wait = true;
     z80->regs.pc++;
     return 4;
 }