From 62019298b90742eab3c2c2970bfedfc9c45cb8f6 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Micha=C3=ABl=20Banaan=20Ananas?=
 <happppp@users.noreply.github.com>
Date: Mon, 15 Oct 2012 14:18:19 +0000
Subject: [PATCH] fixed H flag on SUB/SBB/CMP

---
 src/emu/cpu/i8085/i8085.c    | 15 ++++++---------
 src/emu/cpu/i8085/i8085cpu.h |  7 ++++---
 2 files changed, 10 insertions(+), 12 deletions(-)

diff --git a/src/emu/cpu/i8085/i8085.c b/src/emu/cpu/i8085/i8085.c
index e1992c0b42d..404fca5db01 100644
--- a/src/emu/cpu/i8085/i8085.c
+++ b/src/emu/cpu/i8085/i8085.c
@@ -78,14 +78,12 @@
  * Revisions:
  *
  * xx-xx-2002 Acho A. Tang
- *
  * - 8085 emulation was in fact never used. It's been treated as a plain 8080.
  * - protected IRQ0 vector from being overwritten
  * - modified interrupt handler to properly process 8085-specific IRQ's
  * - corrected interrupt masking, RIM and SIM behaviors according to Intel's documentation
  *
  * 20-Jul-2002 Krzysztof Strzecha
- *
  * - SBB r instructions should affect parity flag.
  *   Fixed only for non x86 asm version (#define i8080_EXACT 1).
  *   There are probably more opcodes which should affect this flag, but don't.
@@ -98,30 +96,24 @@
  *   Thanks for the info go to Anton V. Ignatichev.
  *
  * 08-Dec-2002 Krzysztof Strzecha
- *
  * - ADC r instructions should affect parity flag.
  *   Fixed only for non x86 asm version (#define i8080_EXACT 1).
  *   There are probably more opcodes which should affect this flag, but don't.
  *
  * 05-Sep-2003 Krzysztof Strzecha
- *
  * - INR r, DCR r, ADD r, SUB r, CMP r instructions should affect parity flag.
  *   Fixed only for non x86 asm version (#define i8080_EXACT 1).
  *
  * 23-Dec-2006 Tomasz Slanina
- *
  * - SIM fixed
  *
  * 28-Jan-2007 Zsolt Vasvari
- *
  * - Removed archaic i8080_EXACT flag.
  *
  * 08-June-2008 Miodrag Milanovic
- *
  * - Flag setting fix for some instructions and cycle count update
  *
  * August 2009, hap
- *
  * - removed DAA table
  * - fixed accidental double memory reads due to macro overuse
  * - fixed cycle deduction on unconditional CALL / RET
@@ -133,10 +125,15 @@
  *   fixed X5 / V flags where accidentally broken due to flag names confusion
  *
  * 21-Aug-2009, Curt Coder
- *
  * - added 8080A variant
  * - refactored callbacks to use devcb
  *
+ * October 2012, hap
+ * - fixed H flag on subtraction opcodes
+ * - on 8080, don't push the unsupported flags(X5, X3, V) to stack
+ * - 8080 passes on 8080/8085 CPU Exerciser, 8085 errors only on the DAA test
+ *   (ref: http://www.idb.me.uk/sunhillow/8080.html - tests only 8080 opcodes)
+ *
  *****************************************************************************/
 
 #include "emu.h"
diff --git a/src/emu/cpu/i8085/i8085cpu.h b/src/emu/cpu/i8085/i8085cpu.h
index db8611db4c3..bc4a5297082 100644
--- a/src/emu/cpu/i8085/i8085cpu.h
+++ b/src/emu/cpu/i8085/i8085cpu.h
@@ -85,19 +85,19 @@
 
 #define M_SUB(R) {																	\
 	int q = cpustate->AF.b.h-R;														\
-	cpustate->AF.b.l=ZSP[q&255]|((q>>8)&CF)|((cpustate->AF.b.h^q^R)&HF)|VF;			\
+	cpustate->AF.b.l=ZSP[q&255]|((q>>8)&CF)|(~(cpustate->AF.b.h^q^R)&HF)|VF;		\
 	cpustate->AF.b.h=q;																\
 }
 
 #define M_SBB(R) {																	\
 	int q = cpustate->AF.b.h-R-(cpustate->AF.b.l&CF);								\
-	cpustate->AF.b.l=ZSP[q&255]|((q>>8)&CF)|((cpustate->AF.b.h^q^R)&HF)|VF;			\
+	cpustate->AF.b.l=ZSP[q&255]|((q>>8)&CF)|(~(cpustate->AF.b.h^q^R)&HF)|VF;		\
 	cpustate->AF.b.h=q;																\
 }
 
 #define M_CMP(R) {																	\
 	int q = cpustate->AF.b.h-R;														\
-	cpustate->AF.b.l=ZSP[q&255]|((q>>8)&CF)|((cpustate->AF.b.h^q^R)&HF)|VF;			\
+	cpustate->AF.b.l=ZSP[q&255]|((q>>8)&CF)|(~(cpustate->AF.b.h^q^R)&HF)|VF;		\
 }
 
 #define M_DAD(R) {																	\
@@ -106,6 +106,7 @@
 	cpustate->HL.w.l = q;															\
 }
 
+// DSUB is 8085-only, not sure if H flag handling is correct
 #define M_DSUB(cpustate) {															\
 	int q = cpustate->HL.b.l-cpustate->BC.b.l;										\
 	cpustate->AF.b.l=ZS[q&255]|((q>>8)&CF)|VF|										\