Checkpoint: add printf() for debugging, remove query of E881 (seems

to hang some systems), move E820 table to conventional memory
(sized dynamically), use BIOS memory pointer to determine where in
DOS memory to put our routine.

1 files changed, 39 insertions, 42 deletions

diff --git a/memdisk/memdisk.asm b/memdisk/memdisk.asm
index 3c9513dd..ddaf100b 100644
--- a/memdisk/memdisk.asm
+++ b/memdisk/memdisk.asm
@@ -239,41 +239,37 @@ setup_regs:
 		ret
 
 int15_e820:
-		cmp edx,534D4150h
+		cmp edx,534D4150h	; "SMAP"
 		jne near oldint15
 		cmp ecx,20		; Need 20 bytes
 		jb err86
+		push ds
+		push cs
+		pop ds
 		push edx		; "SMAP"
-		push esi
-		push edi
 		and ebx,ebx
 		jne .renew
-		mov ebx,[E820Table]
-.renew:		mov esi,ebx
-		xor edi,edi
-		mov di,cs
-		shr di,4
-		add edi,E820Buf
-		mov ecx,24/2
-		call bcopy
-		add ebx, byte 12
-		pop edi
-		pop esi
-		mov eax,[cs:E820Buf]
+		mov ebx,E820Table
+.renew:
+		add bx, byte 12		; Advance to next
+		mov eax,[bx-12]		; Start addr (low)
 		mov [es:di],eax
-		mov eax,[cs:E820Buf+4]
-		mov [es:di+4],eax
-		mov eax,[cs:E820Buf+12]
-		mov [es:di+8],eax
-		mov eax,[cs:E820Buf+16]
-		mov [es:di+12],eax
-		mov eax,[cs:E820Buf+8]
+		mov ecx,[bx-8]		; Start addr (high)
+		mov [es:di+4],ecx
+		mov eax,[bx]		; End addr (low)
+		mov ecx,[bx+4]		; End addr (high)
+		sub eax,[bx-12]		; Derive the length
+		sbb ecx,[bx-8]
+		mov [es:di+8],eax	; Length (low)
+		mov [es:di+12],ecx	; Length (high)
+		mov eax,[bx-4]		; Type
 		mov [es:di+16],eax
-		cmp dword [cs:E820Buf+20], byte -1
+		cmp dword [bx+8], byte -1	; Type of next = end?
 		jne .notdone
 		xor ebx,ebx		; Done with table
 .notdone:
 		pop eax			; "SMAP"
+		pop ds
 		mov ecx,20		; Bytes loaded
 int15_success:
 		mov byte [bp+12], 02h	; Clear CF
@@ -412,33 +408,34 @@ Mover_dst2:	db 0			; High 8 bits of source addy
 
 LastStatus	db 0			; Last return status
 
-		section .bss
-		alignb 4
+		alignb 4, db 0
 PatchArea	equ $			; This gets filled in by the installer
 
-Cylinders	resw 1			; Cylinder count
-Heads		resw 1			; Head count
-Sectors		resd 1			; Sector count (zero-extended)
-DiskSize	resd 1			; Size of disk in blocks
-DiskBuf		resd 1			; Linear address of high memory disk
+Cylinders	dw 0			; Cylinder count
+Heads		dw 0			; Head count
+Sectors		dd 0			; Sector count (zero-extended)
+DiskSize	dd 0			; Size of disk in blocks
+DiskBuf		dd 0			; Linear address of high memory disk
 
-E820Table	resd 1			; E820 table in high memory
-Mem1MB		resd 1			; 1MB-16MB memory amount (1K)
-Mem16MB		resd 1			; 16MB-4G memory amount (64K)
-MemInt1588	resd 1			; 1MB-65MB memory amount (1K)
+Mem1MB		dd 0			; 1MB-16MB memory amount (1K)
+Mem16MB		dd 0			; 16MB-4G memory amount (64K)
+MemInt1588	dd 0			; 1MB-65MB memory amount (1K)
 
-OldInt13	resd 1			; INT 13h in chain
-OldInt15	resd 1			; INT 15h in chain
+OldInt13	dd 0			; INT 13h in chain
+OldInt15	dd 0			; INT 15h in chain
 
-OldDosMem	resw 1			; Old position of DOS mem end
+OldDosMem	dw 0			; Old position of DOS mem end
 
-DriveNo		resb 1			; Our drive number
-DriveType	resb 1			; Our drive type (floppies)
+DriveNo		db 0			; Our drive number
+DriveType	db 0			; Our drive type (floppies)
 
 		; End patch area
 
-Stack		resd 2			; Saved SS:ESP on invocation
-E820Buf		resd 6			; E820 fetch buffer
-SavedAX		resw 1			; AX saved on invocation
+Stack		dd 0			; Saved SS:ESP on invocation
+		dw 0
+SavedAX		dw 0			; AX saved on invocation
+
+		alignb 4, db 0		; We *MUST* end on a dword boundary
 
+E820Table	equ $			; The installer loads the E820 table here
 TotalSize	equ $			; End pointer