From: Alan Cox <alan@linux.intel.com>
Date: Sat, 30 May 2015 12:23:28 +0000 (+0100)
Subject: sdltrs: Commit emulator patches
X-Git-Url: https://git.ndcode.org/public/gitweb.cgi?a=commitdiff_plain;h=5d538732aee91cea494cd2c333fb50a8bbaecfaf;p=FUZIX.git

sdltrs: Commit emulator patches

These are needed to run Fuzix reliably
---

diff --git a/Kernel/patches/README b/Kernel/patches/README
index 96070309..497348b8 100644
--- a/Kernel/patches/README
+++ b/Kernel/patches/README
@@ -10,4 +10,17 @@ SDCC:
 	   code is called via push af call foo pop af
 
 
+Note: This patch is now mostly obsolete. Feature #1 is mostly integrated
+into the mainstream SDCC. Feature #2 is only needed for the ZX128 and has
+not yet been ported to a recent compiler
+
+
+
+SDLTRS:
+	Corrects the handling of the IFF flags on interrupt delivery and
+when you do a RETI, which has a subtle difference to a RET. Without these
+fixes Fuzix will crash at random on the emulator.
+
+	For more information on the Z80 IFF flags see section 5.3 of Z80
+Documented: http://www.z80.info/zip/z80-documented.pdf
 
diff --git a/Kernel/patches/sdltrs-fix-iff-flags.patch b/Kernel/patches/sdltrs-fix-iff-flags.patch
new file mode 100644
index 00000000..c7f74bda
--- /dev/null
+++ b/Kernel/patches/sdltrs-fix-iff-flags.patch
@@ -0,0 +1,19 @@
+diff -u --recursive sdltrs_1_1_0/src/z80.c sdltrs_1_1_0.ac/src/z80.c
+--- sdltrs_1_1_0/src/z80.c	2010-02-14 00:38:36.000000000 +0000
++++ sdltrs_1_1_0.ac/src/z80.c	2015-05-30 02:44:06.958734734 +0100
+@@ -1348,6 +1348,7 @@
+     REG_SP -= 2;
+     mem_write_word(REG_SP, REG_PC);
+     z80_state.iff1 = 0;
++    z80_state.iff2 = 0;
+     switch (z80_state.interrupt_mode) {
+     case 0:
+       /* REG_PC = get_irq_vector() & 0x38; */
+@@ -2880,6 +2882,7 @@
+ 
+       case 0x4D:	/* reti */
+ 	/* no support for alerting peripherals, just like ret */
++	z80_state.iff1 = z80_state.iff2;
+ 	REG_PC = mem_read_word(REG_SP);
+ 	REG_SP += 2;
+ 	T_COUNT(14);