From: Alan Cox <alan@linux.intel.com>
Date: Tue, 16 Apr 2019 22:57:09 +0000 (+0100)
Subject: 8085: add hooks for magic Z80 M1 emulation
X-Git-Url: https://git.ndcode.org/public/gitweb.cgi?a=commitdiff_plain;h=77b5bf9545a88d9860ae48785ce9354cfb3bfa87;p=FUZIX.git

8085: add hooks for magic Z80 M1 emulation
---

diff --git a/Kernel/lowlevel-8085.s b/Kernel/lowlevel-8085.s
index 7e920adc..4f72cd7a 100644
--- a/Kernel/lowlevel-8085.s
+++ b/Kernel/lowlevel-8085.s
@@ -297,6 +297,10 @@ interrupt_handler:
 intout:
 	xra a
 	sta U_DATA__U_ININTERRUPT
+
+	FAKE_IRET		! Usually null but some platforms
+				! have hacks for Z80 peripherals
+
 	lda U_DATA__U_INSYS
 	ora a
 	jnz interrupt_pop
@@ -342,6 +346,12 @@ preemption:
 	lhld istack_switched_sp
 	shld U_DATA__U_SYSCALL_SP
 	lxi sp,kstack_top
+
+	!
+	!	So any Z80 style devices see an 'iret'
+	!
+	FAKE_IRET
+
 	!
 	!	Mark ourselves as in a system call
 	!
diff --git a/Kernel/platform-v85/kernel.def b/Kernel/platform-v85/kernel.def
index 91b882e3..e3f55f04 100644
--- a/Kernel/platform-v85/kernel.def
+++ b/Kernel/platform-v85/kernel.def
@@ -17,3 +17,6 @@ CONFIG_SWAP		    = 1
 #define DI		mvi a,0x0a ; sim
 
 #define EI		mvi a,0x08 ; sim
+
+/* We have no Z80 peripherals and no iret fakery */
+#define FAKE_IRET