pentagon: bit more work on this port

This gets us to the point we start init, then everything goes a bit pear
shaped.

- Finish loader
- Sort of mappings
- Set video properties correctly for bank 7
- Enable NemoIDE

Kernel/platform/platform-pentagon/Makefile

@@ -56,16 +56,18 @@ loader.bin: loader.s
 	dd if=loader.tmp bs=2048 skip=15 count=1 conv=sync of=loader.bin
 
 image: loader.bin
-	# Low 16K (will end up in bank 0 0000-3FFF)
-	dd if=../../common.bin bs=16384 conv=sync skip=0 count=1 of=block0
-	# Bank 1 (C000-FFFF)
+	# Common memory 4000-7FFF - bank 5
+	dd if=../../common.bin bs=16384 conv=sync skip=1 count=1 of=block0
+	# CODE1 C000-FFFF - bank 0
 	dd if=../../bank1.bin bs=16384 conv=sync skip=3 count=1 of=block1
-	# Bank 2 (8000-BFFF)
+	# Common memory 8000-BFFF - bank 2
 	dd if=../../common.bin bs=16384 conv=sync skip=2 count=1 of=block2
-	# Bank 6 (C000-FFFF)
+	# CODE2 C000-FFFF - bank 6
 	dd if=../../bank2.bin bs=16384 conv=sync skip=3 count=1 of=block3
-	# Bank 7 (C000-FFFF)
+	# CODE3 C000-FFFF - bank 7 (video)
 	dd if=../../bank3.bin bs=16384 conv=sync skip=3 count=1 of=block4
+	# CODE4 C000-FFFF - bank 3
+	dd if=../../bank4.bin bs=16384 conv=sync skip=3 count=1 of=block5
 
 	cp base-image.trd fuzix.trd
 	# Insert 4K loader
@@ -76,6 +78,7 @@ image: loader.bin
 	../../tools/trdify fuzix.trd BLOCK2 block2
 	../../tools/trdify fuzix.trd BLOCK3 block3
 	../../tools/trdify fuzix.trd BLOCK4 block4
+	../../tools/trdify fuzix.trd BLOCK5 block5
 
 IMAGES = $(FUZIX_ROOT)/Images/$(TARGET)
 

Kernel/platform/platform-pentagon/README

@@ -11,7 +11,7 @@ Then it gets more complicated (and the partial decode ports make it worse)
 
 Pentagon uses bits 7/6 to allow for 512K RAM
 
-ATM us FDFD bits 0-2
+ATM uses FDFD bits 0-2
 
 ----
 These machines all have the same basic problem, there is a 16K window at
@@ -25,16 +25,18 @@ We run with the following mapping
 8400-BFFF	_DISCARD area - blown away when we exec init
 		(tons of room in this space)
 C000-FFFF
-	0:	Kernel CODE4 (lot of room)
-	1:	Kernel CODE (fairly full)
+	0:	Kernel CODE1
+	1:	Kernel CODE2
 	2:	Mapped at 0x8000-0xBFFF (holds current process copy)
-	3:	User process
+	3:	kernel CODE4
 	4:	User process
 	5:	Mapped at 0x4000-0x7FFF (kernel data/common)
-	6:	Kernel CODE2 (fairly full)
-	7:	CODE3, Video (fairly full)
+	6:	User process
+	7:	Kernel CODE3, Video
+	8-15:	User process
+	(32-63: User process on 512K machine)
 
-User processes live in 3/4 and 8+. We have copy stuff back and forth
+User processes live in 4/6 and 8+. We have copy stuff back and forth
 to page 2 due to the memory manager limits.
 
 To Do:

Kernel/platform/platform-pentagon/crt0.s

@@ -54,7 +54,29 @@
 	.include "kernel.def"
 	.include "../../cpu-z80/kernel-z80.def"
 
+	.area _DISCARD
+
+	; Discard starts with the initial bootstrap
+	ld bc,#0x7ffd
+	ld a,#0x14
+	out (c),a		; map the temporary buffer
+	ld hl,#0xC000
+	ld de,#0x4000
+	ld b,d
+	ld c,e
+	ldir			; into position 4000-7FFF
+
+	; Switch to bank 0	(code 1)
+	ld a,#0x08
+	ld bc,#0x7ffd
+	out (c),a
+
+	jp	go
+
+
 	.area _CODE1
+
+go:
         ; startup code
 	;
 	; Entered from the bootstrap with 0-3FFF mapped and loaded as

Kernel/platform/platform-pentagon/devices.c

@@ -37,7 +37,7 @@ bool validdev(uint16_t dev)
 void device_init(void)
 {
 #ifdef CONFIG_TD_IDE
-//  ide_probe();
+  ide_probe();
 #endif
 #ifdef CONFIG_TD_SD
   sd_probe();

Kernel/platform/platform-pentagon/discard.c

@@ -10,8 +10,6 @@ extern uint8_t fuller, kempston, kmouse, kempston_mbmask;
 void pagemap_init(void)
 {
 	uint8_t i;
-	pagemap_add(3);
-	pagemap_add(4);
 
 	/* Pentagon uses 7FFD as follows
 		7: 256K
@@ -21,11 +19,25 @@ void pagemap_init(void)
 		0: 16K
 		
 	   The 1MB one uses bit 5 for 512K */
+
 	/* Add the rest of the first 256K */
+	pagemap_add(0x04);
+	pagemap_add(0x06);
+
+	/* 128-256K */
 	for (i = 0; i < 8; i++)
 		pagemap_add(0x40|i);
-	/* If we deal with Scorpion and friends then we have to use
-	   1FFD bits 4-7 for the high bits instead */
+
+	/* TODO: enable 512K support in pentagon.s */
+	if (ramsize == 512) {
+		for (i = 0; i < 8; i++) {
+			pagemap_add(0x80|i);
+			pagemap_add(0xC0|i);
+		}
+	}
+	/* TODO: 512K is more complex.
+	   - Pentagon 512 uses bits 7/6/2/1/0
+	   - ATM uses FDFD bits 2-0 */
 }
 
 /* string.c

Kernel/platform/platform-pentagon/kernel.def

@@ -12,5 +12,5 @@ PROGLOAD		    .equ 0x8000
 
 NBUFS			    .equ 5
 
-BANK_BITS		    .equ 0x10		; Spectrum ROM select
-						; Doesn't really matter!
+BANK_BITS		    .equ 0x18		; Spectrum ROM select
+						; Video at 0xC000

Kernel/platform/platform-pentagon/loader.s

@@ -3,6 +3,16 @@
 ;
 ;	The disk holds files of the format code{n} where n is the bank to
 ;	place it in. TRDOS is asked to load the lot and then we launch
+;
+;	The on disk layout is
+;
+;	16K common	(0x4000-0x7FFF)		Bank 5 (loaded via 4)
+;	16K bank	(0xC000-0xFFFF)		Bank 0	(CODE1)
+;	16K common	(0x8000-0xBFFF)		Bank 2
+;	16K bank	(0xC000-0xFFFF)		Bank 1	(CODE2)
+;	16K bank	(0xC000-0xFFFF)		Bank 7  (CODE3)
+;	16K bank	(0xC000-0xFFFF)		Bank 3  (CODE4)
+;
 ;
 
 		.module loader
@@ -11,39 +21,34 @@
 
 start:
 		ld sp,#start
-		xor a
+
+		ld a,#4			; common 4000-7FFF temporary copy
 		ld de,#0x0109
-		call trdos		; bank 0	(will appear at 0x0000)
-		inc a
+		call trdos
+
+		xor a			; code 1 into bank 0
 		ld de,#0x0509
-		call trdos		; bank 1	(high bank CODE1)
-		inc a
+		call trdos
+
+		ld a,#2			; common 8000-BFFF into bank 2
 		ld de,#0x0909
-		call trdos		; bank 2	(0x8000-0xBFFF bank)
-		ld a,#6
+		call trdos
+
+		ld a,#1			; code 2 into bank 1
 		ld de,#0x0D09
-		call trdos		; bank 6	(high bank CODE2)
-		inc a
+		call trdos
+
+		ld a,#7			; code  3 into bank 7
 		ld de,#0x1109
-		call trdos		; bank 7	(high bank CODE3)
+		call trdos
+
+		ld a,#3			; code 4 into bank 3
+		ld de,#0x1509
+		call trdos
 
 		di
-		; Turn off low ROM
-		; Some older systems want 0x1FFD bit 0 instead FIXME
-		ld bc,#0xeff7
-		ld a,#0x08
-		out (c),a
-		; The kernel is loaded into 1,6,7
-		; The low memory is loaded into bank 0
-		; The 8000-BFFF range is loaded by the loader
-		; The 4000-7FFF range is zero
 
-		; Switch ROM for bank 0
-		ld a,#0x01
-		ld bc,#0x7ffd
-		out (c),a
-		; FIXME - where is best to start up
-		jp 0xC000
+		jp 0x8400		; into loaded bootstrap
 
 trdos:
 		; Switch bank

Kernel/platform/platform-pentagon/pentagon.s

@@ -11,7 +11,7 @@
 ;	7		CODE 3 + VIDEO + FONTS
 ;	2/5		4000-BFFF (common and user low buffer)
 ;
-;	4		Free
+;	4/6		Free
 ;	8+		Free
 ;
 
@@ -148,6 +148,44 @@ init_early:
 	out (0xFE),a
         ret
 
+	.area _COMMONMEM
+	;
+	;	Set interrupt vectors in each bank. Run from discard
+	;	so we don't page ourself out
+
+_program_vectors:
+	pop bc
+	pop de
+	pop hl			;	task page ptr
+	push hl
+	push de
+	push bc
+	ld a, (hl)		; high page of the pair
+
+setvectors:
+	call map_save_kernel
+	call switch_bank
+	ld a, #0x18
+	ld (0xffff), a		;	JR (plus ROM at 0 gives JR $FFF4)
+	ld a, #0xC3		;	JP
+	ld (0xFFF4), a		;	FFF4-6 are the interrupt vector
+	ld (0xFFF7), a		;	FFF7-9 are syscall
+	ld hl, #interrupt_handler
+	ld (0xFFF5), hl		;	to IRQ handler
+	call map_restore
+	ret
+
+setallvectors:
+	xor a			;	bank 0	(CODE 1)
+	call setvectors
+	ld a, #1		;	bank 1	(CODE 2)
+	call setvectors
+	ld a, #7		;	bank 7	(CODE 3 / VIDEO)
+	call setvectors
+	ld a, #3		;	bank 3	(CODE 4)
+	jr setvectors
+
+
 	.area _VIDEO
 
 init_hardware:
@@ -161,24 +199,17 @@ init_hardware:
 	; 2: 4000-7FFF (screen and buffers)
 	; 3: fourth kernel bank at C000
 	; 5: 8000-BFFF (working 16K copy)
-	; 6: second kernel bank at C000
 	; 7: third kernel bank at C000
 	;
         ld hl, #(256 - 96)
         ld (_procmem), hl
 
-	;
-	;	No low RAM so need IM2 and custom syscall interface
-	;	(will need to tackle that nicely in libc too)
-	;
+	; Set up the vectors on all the kernel pages
+	; user will be set up as we go
+	push af
+	call setallvectors
+	pop af
 
-	ld a,#0xC3
-	ld (0xFFFD),a
-	ld (0xFFF4),a
-	ld hl,#unix_syscall_entry
-	ld (0xFFFE),hl
-	ld hl,#interrupt_handler
-	ld (0xFFF5),hl
         ; screen initialization
 	push af
 	call _vtinit
@@ -195,9 +226,6 @@ init_hardware:
 
         .area _COMMONMEM
 
-_program_vectors:
-	ret
-
 	; Swap helper. Map the page in A into the address space such
 	; that swap_map() gave the correct pointer to use. Undone by
 	; a map_kernel_{restore}

Kernel/platform/platform-pentagon/zxvideo.s

@@ -21,7 +21,7 @@
 	; Build the video library as the only driver
 
 ZXVID_ONLY	.equ	1
-SCREENBASE	.equ 0x40
+SCREENBASE	.equ 0xC0
 
         .area _VIDEO