From 1e1fb0902acff3a9641a0feff0860e5ab9e7bf79 Mon Sep 17 00:00:00 2001
From: Nigel Barnes <Pernod70@users.noreply.github.com>
Date: Mon, 2 Oct 2017 12:07:52 +0100
Subject: [PATCH] acorn_dsk: Improve identifying SSD/DSD by comparing image
 size with sector counts. - Fixed DDCPM format to handle correct image of
 Double Density CP/M.

bbc_flop_z80.xml: Replaced Double Density CP/M with good dump (nw)
---
 hash/bbc_flop_z80.xml         |  4 ++--
 src/lib/formats/acorn_dsk.cpp | 18 ++++++++----------
 2 files changed, 10 insertions(+), 12 deletions(-)

diff --git a/hash/bbc_flop_z80.xml b/hash/bbc_flop_z80.xml
index d5aa7adb178..48e005b3772 100644
--- a/hash/bbc_flop_z80.xml
+++ b/hash/bbc_flop_z80.xml
@@ -160,8 +160,8 @@
 		<info name="format" value="DDCP/M" />
 		<info name="usage" value="Requires Z80 2nd Processor and Opus DDOS" />
 		<part name="flop1" interface="floppy_5_25">
-			<dataarea name="flop" size="811520">
-				<rom name="DDCPM.ssd" size="811520" crc="986d8057" sha1="745bece1a8423fe363fc5a5c72bc64e8c58080df" offset="0" />
+			<dataarea name="flop" size="819200">
+				<rom name="DDCPM.ssd" size="819200" crc="c9d07eff" sha1="ccb1a0076d435ced493775ec8ca2c6c2bf4b5fef" offset="0" />
 			</dataarea>
 		</part>
 	</software>
diff --git a/src/lib/formats/acorn_dsk.cpp b/src/lib/formats/acorn_dsk.cpp
index 486cf20be54..93b9f400db0 100644
--- a/src/lib/formats/acorn_dsk.cpp
+++ b/src/lib/formats/acorn_dsk.cpp
@@ -63,7 +63,7 @@ int acorn_ssd_format::find_size(io_generic *io, uint32_t form_factor)
 				sectors2 = sectors0;
 			}
 
-			if (sectors0 > 0 && sectors0 % 10 == 0 && sectors2 > 0 && sectors2 % 10 == 0)
+			if (sectors0 > 0 && sectors0 % 10 == 0 && sectors2 > 0 && sectors2 % 10 == 0 && size <= (sectors0 + sectors2) * 256)
 				return i;
 		}
 	}
@@ -156,7 +156,7 @@ int acorn_dsd_format::find_size(io_generic *io, uint32_t form_factor)
 
 			LOG_FORMATS("dsd: sector count 2: %d %s\n", sectors2, sectors2 % 10 != 0 ? "invalid" : "");
 
-			if (sectors0 > 0 && sectors0 % 10 == 0 && sectors2 > 0 && sectors2 % 10 == 0)
+			if (sectors0 > 0 && sectors0 % 10 == 0 && sectors2 > 0 && sectors2 % 10 == 0 && size <= (sectors0 + sectors2) * 256)
 				return i;
 		}
 	}
@@ -512,7 +512,7 @@ int acorn_dos_format::identify(io_generic *io, uint32_t form_factor)
 	int type = find_size(io, form_factor);
 
 	if(type != -1)
-		return 90;
+		return 90; 
 	return 0;
 }
 
@@ -564,8 +564,9 @@ int opus_ddcpm_format::identify(io_generic *io, uint32_t form_factor)
 
 	io_generic_read(io, h, 0, 8);
 
-	if (io_generic_size(io) == 811520 && memcmp(h, "Slogger ", 8) == 0)
+	if (io_generic_size(io) == 819200 && memcmp(h, "Slogger ", 8) == 0)
 		return 100;
+	LOG_FORMATS("ddcpm: no match\n");
 	return 0;
 }
 
@@ -584,7 +585,6 @@ bool opus_ddcpm_format::load(io_generic *io, uint32_t form_factor, floppy_image
 // Sector interleave of 2
 //
 	int spt, bps;
-	uint64_t file_offset = 0;
 
 	for (int head = 0; head < 2; head++) {
 		for (int track = 0; track < 80; track++) {
@@ -593,8 +593,8 @@ bool opus_ddcpm_format::load(io_generic *io, uint32_t form_factor, floppy_image
 			spt = 10;
 			desc_pc_sector sects[10];
 			uint8_t sectdata[10*512];
-
-			io_generic_read(io, sectdata, file_offset, spt * bps);
+			
+			io_generic_read(io, sectdata, head * 80 * spt * 512 + track * spt * 512, spt * 512);
 
 			for (int i = 0; i < spt; i++) {
 				sects[i].track = track;
@@ -602,7 +602,7 @@ bool opus_ddcpm_format::load(io_generic *io, uint32_t form_factor, floppy_image
 				sects[i].sector = i;
 				sects[i].size =  mfm ? 2 : 1;
 				sects[i].actual_size = bps;
-				sects[i].data = sectdata + bps * i;
+				sects[i].data = sectdata + i * 512;
 				sects[i].deleted = false;
 				sects[i].bad_crc = false;
 			}
@@ -611,8 +611,6 @@ bool opus_ddcpm_format::load(io_generic *io, uint32_t form_factor, floppy_image
 				build_wd_track_mfm(track, head, image, 100000, 10, sects, 60, 43, 22);
 			else
 				build_wd_track_fm(track, head, image, 50000, 10, sects, 40, 10, 10);
-
-			file_offset += spt * bps;
 		}
 	}