From 9b17be62644fce63c0bf4ee0faad31ddb5d05cfb Mon Sep 17 00:00:00 2001
From: Alan Cox <etchedpixels@gmail.com>
Date: Sun, 29 Dec 2024 14:56:31 +0000
Subject: [PATCH] z80retro: start fixing up the z80retro conversion to the new
 compiler

This gets the SD card and boot sorted but console input is not happy
---
 Kernel/platform/platform-z80retro/Makefile    |  8 +++++---
 .../platform/platform-z80retro/boot-romwbw.S  | 12 +++++------
 Kernel/platform/platform-z80retro/crt0.S      |  2 +-
 Kernel/platform/platform-z80retro/z80retro.S  | 20 ++++++++++++++++++-
 4 files changed, 31 insertions(+), 11 deletions(-)

diff --git a/Kernel/platform/platform-z80retro/Makefile b/Kernel/platform/platform-z80retro/Makefile
index 30cafedd1..8957e2fc5 100644
--- a/Kernel/platform/platform-z80retro/Makefile
+++ b/Kernel/platform/platform-z80retro/Makefile
@@ -64,7 +64,7 @@ image: bootblock
 	perl -lpe '$$_=hex' fuzix.tmpmap | paste -d" " - fuzix.tmpmap  |  sort -n |  cut -d" " -f 2- >../../fuzix.map
 	../../tools/pack85 <../../fuzix.map fuzix.bin ../../fuzix.bin
 	# Attach the kernel to the boot block
-	cat boot-romwbw.bin ../../fuzix.bin >fuzix.romwbw
+	#cat boot-romwbw.bin ../../fuzix.bin >fuzix.romwbw
 
 clean:
 	rm -f $(OBJS) $(JUNK)  core *~
@@ -86,7 +86,9 @@ diskimage: image
 	dd if=$(FUZIX_ROOT)/Standalone/filesystem-src/parttab.40M of=$(IMAGES)/disk.img bs=40017920 conv=sync
 	# Add the file system
 	dd if=$(IMAGES)/filesys.img of=$(IMAGES)/disk.img bs=512 seek=2048 conv=notrunc
-	# Add the kernel
-	dd if=fuzix.romwbw of=$(IMAGES)/disk.img bs=512 seek=2 conv=notrunc
+	# Add the bootstrap
+	dd if=boot-romwbw.bin of=$(IMAGES)/disk.img bs=512 seek=2 conv=notrunc
+	# And kernel
+	dd if=../../fuzix.bin of=$(IMAGES)/disk.img bs=512 seek=4 conv=notrunc
 	# Make an emulator image of it
 	cat $(FUZIX_ROOT)/Standalone/filesystem-src/idehdr.40M $(IMAGES)/disk.img > $(IMAGES)/emu-ide.img
diff --git a/Kernel/platform/platform-z80retro/boot-romwbw.S b/Kernel/platform/platform-z80retro/boot-romwbw.S
index a808f12a1..15684da50 100644
--- a/Kernel/platform/platform-z80retro/boot-romwbw.S
+++ b/Kernel/platform/platform-z80retro/boot-romwbw.S
@@ -72,22 +72,22 @@ bootit:
 	ld e, 32		; 32 sectors (16K)
 	push bc
 	rst 8			; Can error but if so wtf do we do ?
-	ld hl,0x8000
+	ld hl,0x8100
 	ld de,0x0100
-	ld bc,0x4000		; We've loaded 0100-40FF
+	ld bc,0x3F00		; We've loaded 0100-4000
 	ldir
 	pop bc
 	ld hl,0x8000
-	ld e,32		; Load the next 16K
+	ld e,32			; Load the next 16K
 	push bc
 	rst 8
 	ld hl,0x8000		; Move it into place
-	ld de,0x4100
+	ld de,0x4000
 	ld bc,0x4000
 	ldir
 	pop bc
-	ld hl,0x8100		; Now load 8100 up
-	ld e, 55		; takes us up to F100. If that's not enough
+	ld hl,0x8000		; Now load 8000 up
+	ld e, 55		; takes us up to F000. If that's not enough
 				; before unpack we have a problem as we
 				; will need to move the loader
 	rst 8
diff --git a/Kernel/platform/platform-z80retro/crt0.S b/Kernel/platform/platform-z80retro/crt0.S
index 0eefcc092..46e9eb983 100644
--- a/Kernel/platform/platform-z80retro/crt0.S
+++ b/Kernel/platform/platform-z80retro/crt0.S
@@ -12,7 +12,7 @@ init:                       ; must be at 0x0100 as we are loaded at that
 
 	ld	sp, kstack_top
 	; Move the common memory where it belongs
-	ld	hl, __data
+	ld	hl, __bss
 	ld	de, __common
 	ld	bc, __common_size
 	ldir
diff --git a/Kernel/platform/platform-z80retro/z80retro.S b/Kernel/platform/platform-z80retro/z80retro.S
index fda433836..b32c7d84d 100644
--- a/Kernel/platform/platform-z80retro/z80retro.S
+++ b/Kernel/platform/platform-z80retro/z80retro.S
@@ -459,7 +459,10 @@ inchar_s:
 	.export _sd_spi_rx_sector
 
 _sd_spi_tx_byte:
-	ld	e,l
+	pop	hl
+	pop	de
+	push	de
+	push	hl
 sd_tx:
 	; bit 0
 	rl	e
@@ -506,9 +509,12 @@ sd_tx:
 ;	Receive is by far the most important path
 ;
 _sd_spi_rx_byte:
+	push	bc
 	ld	c,0xFF
 	call	sd_rx
+	pop	bc
 	ld	l,e
+	ld	h,0
 	ret
 
 ; FIXME - rotate C
@@ -572,6 +578,11 @@ sd_rx:
 	ret
 
 _sd_spi_rx_sector:
+	pop	de
+	pop	hl
+	push	hl
+	push	de
+	push	bc
 	ld	bc,0xFF		; 0 for count 255 for reload of A
 	ld	a,(_td_raw)
 	or	a
@@ -591,9 +602,15 @@ rx_byte:
 	ld	(hl),e
 	inc	hl
 	djnz	rx_byte
+	pop	bc
 	jp	map_kernel
 
 _sd_spi_tx_sector:
+	pop	de
+	pop	hl
+	push	hl
+	push	de
+	push	bc
 	ld	b,0
 	ld	a,(_td_raw)
 	or	a
@@ -613,6 +630,7 @@ tx_byte:
 	inc	hl
 	call	sd_tx
 	djnz	tx_byte
+	pop	bc
 	jp	map_kernel
 
 ;