From 2ac8d1308a5ded5b64bbb3de50c79dda430f387c Mon Sep 17 00:00:00 2001
From: Tolik <85737314+Tolik-Trek@users.noreply.github.com>
Date: Wed, 3 Jul 2024 00:15:25 +1000
Subject: [PATCH] core: fixed a bug for FAT32 with an unusually large FAT size
 and added another bug

---
 BOOT/DSSBOOT.ASM              | 59 ++++++++++++++++++++++++-----------
 DSS/API/ChnDisk.asm           | 39 +++++++++++------------
 DSS/DOS_Proc.asm              | 14 ++++-----
 DSS/FS/FAT/FAT.asm            | 57 ++++++++++++++++++++++++---------
 DSS/build.txt                 |  2 +-
 DSS/drivers/media/fdd-drv.asm | 11 +++----
 SHELL/Commands/INFO.ASM       |  4 ++-
 SHELL/build.txt               |  2 +-
 8 files changed, 119 insertions(+), 69 deletions(-)

diff --git a/BOOT/DSSBOOT.ASM b/BOOT/DSSBOOT.ASM
index 00892ce..60c13f0 100644
--- a/BOOT/DSSBOOT.ASM
+++ b/BOOT/DSSBOOT.ASM
@@ -392,18 +392,15 @@ YEPDOS:		;[ ] 17.12.2023 
 		;
 
 ;
-GET_BPB:	LD	HL,#0000
-		;
+GET_BPB:	XOR	A
+		LD	H,A
+		LD	L,A
 		LD	(FatBuffer.FAT1_SEC_H),HL  ; high word first sector FAT #1
 		LD	(FatBuffer.RootDirFirstSector_H),HL
-		;LD	(FatBuffer.CacheBlock),HL
-		XOR	A
 		LD	(FatBuffer.SectorsPerFAT_H),A
 		;
 		PUSH	HL
 		POP	IX
-		; LD	IX,#0000
-		; LD	HL,#0000
 		LD	DE,BOOT_BUFFER
 		LD	BC,1*256 + BIOS.DRV_READ
 		LD	A,(DRIVE)
@@ -458,34 +455,59 @@ GET_BPB:	LD	HL,#0000
 		LD	HL,(BOOT_BUFFER + BOOT_SECTOR.RESERVED_SECTORS)
 		LD	(FatBuffer.FAT1_SEC_L),HL  ; low word first sector FAT #1
 		;
-		LD	BC,0
+	XOR	A
+	LD	B,A
+	LD	C,A
+	EXX
+	 LD	H,A
+	 LD	L,A
+	 LD	D,A
+	 LD	E,A
+	EXX
+		;
+	;LD	BC,0
 		LD	DE,(BOOT_BUFFER + BOOT_SECTOR.SectorsPerFAT16)
 		LD	A,E
 		OR	D
 		JR	NZ,.skip_high
 		;
-		LD	BC,(BOOT_BUFFER + BOOT_SECTOR.SectorsPerFAT32 + 2)
-		LD	A,C
+	EXX
+	 LD	DE,(BOOT_BUFFER + BOOT_SECTOR.SectorsPerFAT32 + 2)
+	 LD	A,E
+	EXX
+	;LD	BC,(BOOT_BUFFER + BOOT_SECTOR.SectorsPerFAT32 + 2)
+	;LD	A,C
 		LD	(FatBuffer.SectorsPerFAT_H),A
 		LD	DE,(BOOT_BUFFER + BOOT_SECTOR.SectorsPerFAT32)
+		;
 .skip_high:	LD	(FatBuffer.SectorsPerFAT_L),DE
 		LD	A,(BOOT_BUFFER + BOOT_SECTOR.Number_of_FATs)   ;	amount FATs
 		CP	1
 		JR	Z,.one_FAT
 		DEC	A
 		ADD	HL,DE
-		JR	NC,.no_inc_BC
-		INC	BC
+	EXX
+	 ADC	HL,DE
+	EXX
+	;JR	NC,.no_inc_BC
+	;INC	BC
 .no_inc_BC:	;
 .one_FAT:	;
 .loop1:		ADD	HL,DE
-		JR	NC,.loop1_1
-		INC	BC
+	EXX
+	 ADC	HL,DE
+	EXX
+	;JR	NC,.loop1_1
+	;INC	BC
 .loop1_1:	DEC	A
 		JR	NZ,.loop1
 		;
 		LD	(FatBuffer.RootDirFirstSector_L),HL  ; first sector DIR
-		LD	(FatBuffer.FirstDataSector_H),BC
+	EXX
+	 ; можно сразу тут загнать старший байт, потому-что дла FAT32 следующий расчёт - это прибавление нуля.
+	 LD	(FatBuffer.FirstDataSector_H),HL
+	EXX
+	;LD	(FatBuffer.FirstDataSector_H),BC
 		LD	BC,(BOOT_BUFFER + BOOT_SECTOR.BytesPerSector)
 		LD	A,B
 		AND	A
@@ -534,11 +556,10 @@ GET_BPB:	LD	HL,#0000
 		 JP	NC,.loop3
 .loop3.end:	;
 		LD	(FatBuffer.BytesPerCluster),HL
-		; LD	DE,#8001 ; проверка на размер кластера больше 32 кб - не поддерживается ; !TODO
-		; AND	A
-		; SBC	HL,DE
-		; CCF
-		; RET	C	; [ ] fixed bug, thanks to @Romychs (Roman Boykov)
+		; проверка на размер кластера больше 32 кб - не поддерживается ; !TODO
+		 ; .....
+		;
+////////////////////////////////////////////////////////////////////////
 		;
 		LD	HL,(BOOT_BUFFER + BOOT_SECTOR.SectorsPerDrive)
 		LD	BC,0
diff --git a/DSS/API/ChnDisk.asm b/DSS/API/ChnDisk.asm
index 9a8cc87..119846c 100644
--- a/DSS/API/ChnDisk.asm
+++ b/DSS/API/ChnDisk.asm
@@ -2,24 +2,23 @@
 ;
 ;
 ////////////////////////////////////////////////////////////////////////
-CHNDISK_FN:
-	CALL	CHNDISK
-	RET	C
-	PUSH	AF
-	CALL	DIR_PATH_CHANGE.FullCurrent
-	POP	AF
-	RET
-CHNDISK:;[x] более корректная смена диска
-	 CALL	OPENDSK
-	;
-	;R010
-	 RET    C
-	 LD	HL,CORE_BUFFERS.WorkDirectory
-	 LD	(HL),0
-	 PUSH	AF
-	 CALL	OPENDIR
-	 POP	BC
-	 RET	C
-	 LD	A,B
-	RET
+CHNDISK_FN:	CALL	CHNDISK
+		RET	C
+		PUSH	AF
+		CALL	DIR_PATH_CHANGE.FullCurrent
+		POP	AF
+		RET
+CHNDISK:	;[x] более корректная смена диска
+		 CALL	OPENDSK
+		;
+		;R010
+		 RET    C
+		 LD	HL,CORE_BUFFERS.WorkDirectory
+		 LD	(HL),0
+		 PUSH	AF
+		 CALL	OPENDIR
+		 POP	BC
+		 RET	C
+		 LD	A,B
+		RET
 ;
\ No newline at end of file
diff --git a/DSS/DOS_Proc.asm b/DSS/DOS_Proc.asm
index 108e827..0ff063e 100644
--- a/DSS/DOS_Proc.asm
+++ b/DSS/DOS_Proc.asm
@@ -184,13 +184,13 @@ OPENDSK:	;!TEST DRV.Open 
 		 LD	C,A
 		 LD	A,(CORE_BUFFERS.FatBuffer.DRIVE)
 		 CP	C
-		 	IF CHECK_DRIVE_CHANGE
-		 	 JR	NZ,.open
-		 	 PUSH	BC
-		 	 LD	C,Dss.DRV.MediaCheck
-		 	 RST	ToDSS.DRV
-		 	 POP	BC
-			ENDIF
+	IF CHECK_DRIVE_CHANGE
+	 	JR	NZ,.open
+		PUSH	BC
+		LD	C,Dss.DRV.MediaCheck
+		RST	ToDSS.DRV
+		POP	BC
+	ENDIF
 		 JR	Z,.exit
 
 .open:		 LD	A,C
diff --git a/DSS/FS/FAT/FAT.asm b/DSS/FS/FAT/FAT.asm
index 57399db..1c2fc22 100644
--- a/DSS/FS/FAT/FAT.asm
+++ b/DSS/FS/FAT/FAT.asm
@@ -534,7 +534,7 @@ LOADDIR:	;!TODO optimize
 		RET
 		;
 .LoadRootDir:	LD	HL,(CORE_BUFFERS.FatBuffer.RootDirFirstSector_H)	;!TODO возможно, хватит LD HL,0
-		LD	IX,(CORE_BUFFERS.FatBuffer.RootDirFirstSector_L)		; номер лог. сектора
+		LD	IX,(CORE_BUFFERS.FatBuffer.RootDirFirstSector_L)	; номер лог. сектора
 		LD	A,(CORE_BUFFERS.FatBuffer.DirSizeInSectors)
 		LD	B,32	; !HARDCODE sector size 512. 16384/(sector 512). размер root-каталога
 		CP	B
@@ -727,15 +727,25 @@ RD_BPB:			; LD	C,SLOT3
 		 ;LD	(CORE_BUFFERS.FatBuffer.END_CHAIN_CLUSTER_H),BC					; [ ] fat32 reset variables
 		;
 		;
+		EXX	
+		 LD	H,A
+		 LD	L,A
+		 LD	D,A
+		 LD	E,A
+		EXX
 		LD	DE,(CORE_BUFFERS.SECTOR_BUFFER + BOOT_SECTOR.SectorsPerFAT16)
 		LD	A,E
 		OR	D
 		JR	NZ,.skip_high
 		;
-		LD	BC,(CORE_BUFFERS.SECTOR_BUFFER + BOOT_SECTOR.SectorsPerFAT32 + 2)
-		LD	A,C
+		EXX
+		 LD	DE,(CORE_BUFFERS.SECTOR_BUFFER + BOOT_SECTOR.SectorsPerFAT32 + 2)
+		 LD	A,E
+		EXX
+		;
 		LD	(CORE_BUFFERS.FatBuffer.SectorsPerFAT_H),A
 		LD	DE,(CORE_BUFFERS.SECTOR_BUFFER + BOOT_SECTOR.SectorsPerFAT32)
+		;
 .skip_high:	LD	(CORE_BUFFERS.FatBuffer.SectorsPerFAT_L),DE
 		LD	A,(CORE_BUFFERS.SECTOR_BUFFER + BOOT_SECTOR.Number_of_FATs)   ;	amount FATs
 		LD	(CORE_BUFFERS.FatBuffer.Number_Of_FATs),A
@@ -744,18 +754,29 @@ RD_BPB:			; LD	C,SLOT3
 		DEC	A
 		ADD	HL,DE
 		LD	(CORE_BUFFERS.FatBuffer.FAT2_SEC_L),HL
-		JR	NC,.no_inc_BC
-		INC	BC
-.no_inc_BC:	LD	(CORE_BUFFERS.FatBuffer.FAT2_SEC_H),BC
-.one_FAT:	;C_DATA1
+		EXX
+		 ADC	HL,DE
+		 LD	(CORE_BUFFERS.FatBuffer.FAT2_SEC_H),HL
+		EXX
+		;JR	NC,.no_inc_BC
+		;INC	BC
+.no_inc_BC:;LD	(CORE_BUFFERS.FatBuffer.FAT2_SEC_H),BC
+.one_FAT:	;
 .loop1:		ADD	HL,DE
-		JR	NC,.loop1_1
-		INC	BC
+		;JR	NC,.loop1_1
+		;INC	BC
+		EXX
+		 ADC	HL,DE
+		EXX		
 .loop1_1:	DEC	A
 		JR	NZ,.loop1
 		;
 		LD	(CORE_BUFFERS.FatBuffer.RootDirFirstSector_L),HL  ; first sector DIR
-		LD	(CORE_BUFFERS.FatBuffer.FirstDataSector_H),BC
+		EXX
+		 ; можно сразу тут загнать старший байт, потому-что дла FAT32 следующий расчёт - это прибавление нуля.
+		 LD	(CORE_BUFFERS.FatBuffer.FirstDataSector_H),HL
+		EXX
+		;LD	(CORE_BUFFERS.FatBuffer.FirstDataSector_H),BC
 		;
 		LD	BC,(CORE_BUFFERS.FatBuffer.BytesPerSector)
 		LD	A,B
@@ -838,19 +859,27 @@ RD_BPB:			; LD	C,SLOT3
 ////////////////////////////////////////////////////////////////////////
 		; [ ] fat32
 		LD	HL,(CORE_BUFFERS.SECTOR_BUFFER + BOOT_SECTOR.SectorsPerDrive)
-		LD	DE,(CORE_BUFFERS.FatBuffer.FirstDataSector_L)
 		LD	A,H
 		OR	L
 		JP	NZ,.HDDSMAL
 		;
+		LD	DE,(CORE_BUFFERS.FatBuffer.FirstDataSector_L)
+		EXX
+		 LD	HL,(CORE_BUFFERS.SECTOR_BUFFER + BOOT_SECTOR.BPB_BIG_TOTAL_SECTORS_H)
+		 LD	DE,(CORE_BUFFERS.FatBuffer.FirstDataSector_H)	
+		EXX
 		LD	HL,(CORE_BUFFERS.SECTOR_BUFFER + BOOT_SECTOR.BPB_BIG_TOTAL_SECTORS_L)
-		LD	BC,(CORE_BUFFERS.SECTOR_BUFFER + BOOT_SECTOR.BPB_BIG_TOTAL_SECTORS_H)
 		PUSH	BC		; Total Sectors high
 		PUSH	HL		; Total Sectors low
 		AND	A
 		SBC	HL,DE
-		JP	NC,.HDDBIG
-		DEC	BC
+		EXX	
+		 SBC	HL,DE
+		 PUSH	HL
+		EXX
+		POP	BC
+	 	;JP	NC,.HDDBIG
+	 	;DEC	BC
 		JP	.HDDBIG
 		;
 .HDDSMAL:	; CF = 0
diff --git a/DSS/build.txt b/DSS/build.txt
index b92b677..d8292c2 100644
--- a/DSS/build.txt
+++ b/DSS/build.txt
@@ -1 +1 @@
-995
\ No newline at end of file
+996
\ No newline at end of file
diff --git a/DSS/drivers/media/fdd-drv.asm b/DSS/drivers/media/fdd-drv.asm
index d07437e..e196213 100644
--- a/DSS/drivers/media/fdd-drv.asm
+++ b/DSS/drivers/media/fdd-drv.asm
@@ -210,7 +210,7 @@ GetBPB:		LD	IX,0
 		POP	DE
 		POP	HL
 		RET	C
-		LD	BC,#0018
+		LD	BC,BOOT_SECTOR.SectorsPerTrack
 		ADD	HL,BC
 		LD	E,(HL)
 		PUSH	DE
@@ -293,7 +293,7 @@ GenIOCTL:	BIT	7,B
 ;	BC'	 - SECTORS PER TRACK ON PHISICAL DISK
 ;	 A'	 - PHISICAL DRIVE NUMBER
 ;	 A	 - EXTENDED INFORMATION
-;		 D0...D3 - "0" RESERVED (MAY BE OTHER)
+;		 D1..D3 - "0" RESERVED (MAY BE OTHER)
 ;		 D4	- DEVICE MASTER/SLAVE
 ;		 D5	- "1" RESERVED
 ;		 D6	- ADDRESSING MODE LBA/CHS
@@ -340,25 +340,24 @@ GenIOCTL:	BIT	7,B
 		OR	E
 		JR	NZ,.mull_loop2
 		;
-		; A=0 ZF=0 CF=0
+		; A=0 DE=0 ZF=0 CF=0
 		EX	AF,AF'
 		LD	E,A
 		EX	DE,HL
+		; H=0
+		LD	C,H	;[x] 17.12.2023 загрузка с активного раздела, а не с первого
 		EXX 
 		 POP	DE
 		 POP	HL
 		 POP	AF
 		 EX	AF,AF'
 		 ; A=0 ZF=0 CF=0
-		 LD	A,B
 		 LD	B,0
 		 LD	C,L
 		 LD	L,H
 		 LD	H,B
 		 EX	DE,HL
 		EXX
-		; A=0 ZF=0 CF=0
-		LD	C,0	;[x] 17.12.2023 загрузка с активного раздела, а не с первого	
 		AND	A
 		RET 
 		;
diff --git a/SHELL/Commands/INFO.ASM b/SHELL/Commands/INFO.ASM
index 4e4a9d8..ec82682 100644
--- a/SHELL/Commands/INFO.ASM
+++ b/SHELL/Commands/INFO.ASM
@@ -83,11 +83,13 @@ cmd_info:	CALL	Get_Path
 		POP	BC
 		PUSH	BC
 		LD	A,C
+		CP	"C"
+		JR	C,.ItIsFDD
 		LD	DE,Dss.DRV.GenIOCTL.Enter
 		LD	BC,Dss.DRV.GenIOCTL.GetParams
 		RST	ToDSS.DRV			; !FIXIT не возвращает размер сектора, поэтому хардкор по 512
 		JR	NC,.calc_size
-		;
+.ItIsFDD:	;
 		LD	HL,.Unknown_str
 		LD	DE,Buffers.bat_params.PRM5	; Drive size
 		CALL	ncopy_string
diff --git a/SHELL/build.txt b/SHELL/build.txt
index 1fde752..5a40cf6 100644
--- a/SHELL/build.txt
+++ b/SHELL/build.txt
@@ -1 +1 @@
-434
\ No newline at end of file
+435
\ No newline at end of file