From db2b6d996608f7323b04dcf425bee2796a36dbbe Mon Sep 17 00:00:00 2001
From: kub <derkub@gmail.com>
Date: Fri, 12 Apr 2024 20:29:50 +0200
Subject: [PATCH] core z80, fix cycle counting in reset state

---
 pico/debug.c    | 2 +-
 pico/pico.c     | 3 +--
 pico/pico_cmn.c | 2 +-
 pico/pico_int.h | 4 ++--
 pico/sms.c      | 2 +-
 5 files changed, 6 insertions(+), 7 deletions(-)

diff --git a/pico/debug.c b/pico/debug.c
index e928d73b..5a85a30a 100644
--- a/pico/debug.c
+++ b/pico/debug.c
@@ -389,7 +389,7 @@ void PDebugZ80Frame(void)
   else
     lines = 262;
 
-  z80_resetCycles();
+  z80_resetCycles(Pico.t.z80c_aim);
   PsndStartFrame();
 
   if (/*Pico.m.z80Run &&*/ !Pico.m.z80_reset && (PicoIn.opt&POPT_EN_Z80)) {
diff --git a/pico/pico.c b/pico/pico.c
index 34026577..d913e082 100644
--- a/pico/pico.c
+++ b/pico/pico.c
@@ -72,8 +72,6 @@ void PicoPower(void)
   memset(&Pico.m,0,sizeof(Pico.m));
   memset(&Pico.t,0,sizeof(Pico.t));
 
-  z80_reset();
-
   // my MD1 VA6 console has this in IO
   PicoMem.ioports[1] = PicoMem.ioports[2] = PicoMem.ioports[3] = 0xff;
 
@@ -169,6 +167,7 @@ int PicoReset(void)
 
   memset(&PicoIn.padInt, 0, sizeof(PicoIn.padInt));
 
+  z80_reset();
   if (PicoIn.AHW & PAHW_SMS) {
     PicoResetMS();
     return 0;
diff --git a/pico/pico_cmn.c b/pico/pico_cmn.c
index c3b14caa..519aba35 100644
--- a/pico/pico_cmn.c
+++ b/pico/pico_cmn.c
@@ -141,8 +141,8 @@ static int PicoFrameHints(void)
 
   skip = PicoIn.skipFrame;
 
+  z80_resetCycles(cycles_68k_to_z80(Pico.t.m68c_aim - Pico.t.m68c_frame_start));
   Pico.t.m68c_frame_start = Pico.t.m68c_aim;
-  z80_resetCycles();
   PsndStartFrame();
 
   hint = pv->hint_cnt;
diff --git a/pico/pico_int.h b/pico/pico_int.h
index d39e9809..c576ecbf 100644
--- a/pico/pico_int.h
+++ b/pico/pico_int.h
@@ -201,8 +201,8 @@ extern struct DrZ80 drZ80;
 
 #define Z80_STATE_SIZE 0x60
 
-#define z80_resetCycles() \
-  Pico.t.z80c_cnt -= Pico.t.z80c_aim, Pico.t.z80c_aim = Pico.t.z80_scanline = 0
+#define z80_resetCycles(aim) \
+  Pico.t.z80c_cnt -= (aim < Pico.t.z80c_cnt ? aim : Pico.t.z80c_cnt), Pico.t.z80c_aim = Pico.t.z80_scanline = 0
 
 #define z80_cyclesDone() \
   (Pico.t.z80c_aim - z80_cyclesLeft)
diff --git a/pico/sms.c b/pico/sms.c
index 6b1425b2..e954bc8b 100644
--- a/pico/sms.c
+++ b/pico/sms.c
@@ -846,7 +846,7 @@ void PicoFrameMS(void)
   int nmi;
   int y;
 
-  z80_resetCycles();
+  z80_resetCycles(Pico.t.z80c_aim);
   PsndStartFrame();
 
   // for SMS the pause button generates an NMI, for GG ths is not the case
-- 
2.39.5