From: Toni Wilen <twilen@winuae.net>
Date: Wed, 27 Mar 2024 18:15:32 +0000 (+0200)
Subject: Correct calculation of vertical period if NTSC + LOLDIS.
X-Git-Tag: 5300~65
X-Git-Url: https://git.unchartedbackwaters.co.uk/w/?a=commitdiff_plain;h=1964867d164b9c99e2702bd1dca7103a8ed1d78d;p=francis%2Fwinuae.git

Correct calculation of vertical period if NTSC + LOLDIS.
---

diff --git a/custom.cpp b/custom.cpp
index e86fbc10..6942e252 100644
--- a/custom.cpp
+++ b/custom.cpp
@@ -7112,9 +7112,10 @@ static void init_beamcon0(bool fakehz)
 		hardwired_vbstrt = maxvpos;
 		equ_vblank_endline = EQU_ENDLINE_NTSC;
 		equ_vblank_toggle = false;
-		vblank_hz_shf = clk / ((maxvpos + 0.0f) * (maxhpos + 0.5f));
-		vblank_hz_lof = clk / ((maxvpos + 1.0f) * (maxhpos + 0.5f));
-		vblank_hz_lace = clk / ((maxvpos + 0.5f) * (maxhpos + 0.5f));
+		float half = (beamcon0 & BEAMCON0_LOLDIS) ? 0 : 0.5f;
+		vblank_hz_shf = clk / ((maxvpos + 0.0f) * (maxhpos + half));
+		vblank_hz_lof = clk / ((maxvpos + 1.0f) * (maxhpos + half));
+		vblank_hz_lace = clk / ((maxvpos + 0.5f) * (maxhpos + half));
 	}
 
 	dmal_htotal_mask = 0xffff;
@@ -7393,10 +7394,11 @@ static void init_beamcon0(bool fakehz)
 	}
 
 	if (beamcon0 & BEAMCON0_VARBEAMEN) {
-		vblank_hz_nom = vblank_hz = clk / (maxvpos * maxhpos);
+		float half = (beamcon0 & BEAMCON0_PAL) ? 0: ((beamcon0 & BEAMCON0_LOLDIS) ? 0 : 0.5f);
+		vblank_hz_nom = vblank_hz = clk / (maxvpos * (maxhpos + half));
 		vblank_hz_shf = vblank_hz;
-		vblank_hz_lof = clk / ((maxvpos + 1.0f) * maxhpos);
-		vblank_hz_lace = clk / ((maxvpos + 0.5f) * maxhpos);
+		vblank_hz_lof = clk / ((maxvpos + 1.0f) * (maxhpos + half));
+		vblank_hz_lace = clk / ((maxvpos + 0.5f) * (maxhpos + half));
 
 		maxvpos_nom = maxvpos;
 		maxvpos_display = maxvpos;