From 885b74d9b7963514cdf699ea92566ca2496447ca Mon Sep 17 00:00:00 2001
From: Alan Cox <alan@linux.intel.com>
Date: Mon, 18 Feb 2019 00:04:20 +0000
Subject: [PATCH] v85: switch to vectored interrupts and use some 8085
 optimizations

---
 Kernel/platform-v85/README     | 19 ++++++++
 Kernel/platform-v85/config.h   |  3 ++
 Kernel/platform-v85/kernel.def |  8 ++++
 Kernel/platform-v85/tricks.s   |  6 ++-
 Kernel/platform-v85/v85.s      | 82 +++++++++++++++++++++++-----------
 5 files changed, 89 insertions(+), 29 deletions(-)

diff --git a/Kernel/platform-v85/README b/Kernel/platform-v85/README
index d366d45f..be6e7cb2 100644
--- a/Kernel/platform-v85/README
+++ b/Kernel/platform-v85/README
@@ -2,3 +2,22 @@ This is an emulated platform driver for the V85 virtual 8085. The main goal is
 to see what can be done to improve 8085 over 8080. It also provides a way to test
 the IDE and modern block layer code with ackcc.
 
+TODO
+
+Review fast bank copiers to see what a slower but saner one might look like
+so we can keep interrupts on
+
+Perhaps repeats of:
+
+		lhlx
+		mov a,b
+		out a
+		shlx
+		mov a,c
+		out a
+		inx
+		inx
+
+		pop b
+		dex b
+		jnk loop ...
diff --git a/Kernel/platform-v85/config.h b/Kernel/platform-v85/config.h
index 3c869e5d..791c2938 100644
--- a/Kernel/platform-v85/config.h
+++ b/Kernel/platform-v85/config.h
@@ -18,6 +18,9 @@
 #define MAX_MAPS	7
 #define MAP_SIZE	0xC000U
 
+/* We are using the RIM/SIM masking for interrupt control not hard di/ei pairs */
+#define CONFIG_SOFT_IRQ
+
 /* Read processes and big I/O direct into process space */
 #define CONFIG_LARGE_IO_DIRECT(x)	1
 
diff --git a/Kernel/platform-v85/kernel.def b/Kernel/platform-v85/kernel.def
index 4077bba4..91b882e3 100644
--- a/Kernel/platform-v85/kernel.def
+++ b/Kernel/platform-v85/kernel.def
@@ -9,3 +9,11 @@ PROGBASE		    = 0x0000
 PROGLOAD		    = 0x0100
 
 CONFIG_SWAP		    = 1
+
+#define INT_ENTER	mvi a,0x0a ; sim ; ei
+
+#define INT_EXIT	mvi a,0x08 ; di ; sim
+
+#define DI		mvi a,0x0a ; sim
+
+#define EI		mvi a,0x08 ; sim
diff --git a/Kernel/platform-v85/tricks.s b/Kernel/platform-v85/tricks.s
index 66623cd0..11f32f1d 100644
--- a/Kernel/platform-v85/tricks.s
+++ b/Kernel/platform-v85/tricks.s
@@ -8,8 +8,9 @@
 .define bankfork
 
 bankfork:
-	sta patch1+1
-	mov a,c
+	di			! This nasty hack requires we really block
+	sta patch1+1		! interrupts. Might be good to go to a cleaner
+	mov a,c			! approach on a faster 8085 ?
 	sta patch2+1
 	lxi h,0
 	dad sp
@@ -40,6 +41,7 @@ copy_stack:
 copy_done:
 	lxi h,0
 	sphl
+	ei
 	ret
 
 copier:
diff --git a/Kernel/platform-v85/v85.s b/Kernel/platform-v85/v85.s
index 3a6b96e2..3d4b5f16 100644
--- a/Kernel/platform-v85/v85.s
+++ b/Kernel/platform-v85/v85.s
@@ -24,6 +24,41 @@ platform_interrupt_all:
 
 .sect .text
 
+!
+!	Vectored interrupt support. We block only the timer interrupt
+!
+.define _di
+
+_di:
+	lxi h,_int_disabled
+	mvi a,0x0A		! disable timer not serial
+	sim
+	mov a,m
+	mvi m,1
+	mov e,a
+	ret
+
+.define _ei
+
+_ei:
+	xra a
+	sta _int_disabled
+	mvi a,0x08
+	sim
+	ret
+
+.define _irqrestore
+
+_irqrestore:
+	ldsi 2
+	mov a,m
+	sta _int_disabled
+	ora a
+	rnz
+	mvi a,0x08
+	sim
+	ret
+
 .define init_early
 
 init_early:
@@ -59,10 +94,8 @@ _int_disabled:
 
 _program_vectors:
 	di
-	pop d
-	pop h
-	push h
-	push d
+	ldsi 2
+	lhlx
 	call map_process
 	call _program_vectors_u
 	call map_kernel_di
@@ -190,11 +223,8 @@ map_restore:
 .define _probe_bank
 
 _probe_bank:
-	pop d
-	pop h
-	push h
-	push d
-	mov a,l
+	ldsi 2
+	ldax d
 	call map_process_a
 	lxi d,-1
 	lxi h,4
@@ -247,10 +277,11 @@ _ttyready:
 .define _acia_poll
 
 !
-!	Call with interrupts off
+!	Call with interrupts on (we may have some masked)
 !
 _acia_poll:
 	lxi h,acia_queue+1
+	di
 	mov a,m			! read pointer
 	mov e,a			! save it
 	dcx h			! queue pointer
@@ -263,9 +294,11 @@ _acia_poll:
 	mvi d,0
 	dad d			! plus offset
 	mov e,m			! return char in DE
+	ei
 	mvi d,0
 	ret
 empty:
+	ei
 	lxi d,0xffff		! No luck
 	ret
 
@@ -318,11 +351,8 @@ acia_queue:
 .define _devide_writeb
 
 _devide_readb:
-	pop h
-	pop d
-	push d
-	push h
-	mov a,e
+	ldsi 2
+	ldax d
 	sta .patch1+1
 .patch1:
 	in 0
@@ -331,13 +361,11 @@ _devide_readb:
 	ret
 
 _devide_writeb:
-	lxi h,2
-	dad sp
-	mov a,m
+	ldsi 2
+	ldax d
 	sta .patch2+1
-	inx h
-	inx h
-	mov a,m
+	ldsi 4
+	ldax d
 .patch2:
 	out 0
 	ret
@@ -347,10 +375,10 @@ _devide_writeb:
 
 _devide_read_data:
 	push b
-	lxi h,_blk_op
-	mov e,m
+	lxi d,_blk_op
+	lhlx			! Address in HL
+	xchg			! Address in DE, struct back in HL
 	inx h
-	mov d,m			! Address
 	inx h
 	mov a,m			! Mapping type
 	cpi 2
@@ -383,10 +411,10 @@ readloop:
 
 _devide_write_data:
 	push b
-	lxi h,_blk_op
-	mov e,m
+	lxi d,_blk_op
+	lhlx
+	xchg
 	inx h
-	mov d,m
 	inx h
 	mov a,m
 	cpi 2
-- 
2.34.1