The latest version of my emulator:

New stuff:
- Updated framerate to include IPS/KIPS/MIPS(Instructions Per Second).
- Floppy: fixed partly filling during data transfers, implemented Fix drive data/Specify command and MT bit supported.
- Fixed timing issues (mainly with the new MIDI player support) and various timing bugs.
- Added MIDI options to the emulator (in the BIOS, goto Advanced, a new option for MIDI settings has been added):
-- Soundfont: Select the soundfont to use for rendering MIDI sounds. In older versions this was locked to MPU.SF2. Now you can choose it (it still requires a reboot to apply).
-- MIDI player: Select the file with up and down, press Cross/Play to play, Circle/Stop to stop playing and select a new file, press circle again to quit the player and return to the BIOS MIDI menu.
- Multiple SDL locks have been added to improve stability during runtime. Although it still seems to hang when debugging from Visual C++ when trying to terminate the application.
- The updated BIOS settings (BIOS.DAT) is incompatible with the previous BIOS settings (new data has been inserted). This has increased the BIOS.DAT version number (to version 2), making it incompatible with older BIOS.DAT versions. The BIOS.DAT loader has been updated to allow future updates of BIOS.DAT to read the current BIOS.DAT version, providing that the version number matches and the checksum is correct (new features will, by default, leave new settings zeroed, thus making the checksum identical (32-bit CRC)? Thus new BIOS data being non-existant in the file and zeroed by default before loading, will cause the BIOS to stay valid (since zero is added to the checksum(new fields appended to the configuration), the new fields will have it's default values set, and the checksum has nothing added, making a valid BIOS)?

The PSP version currently doesn't work anymore (it hangs when trying to initialise the video font color). This will need to be fixed later. Currently SDL locks have been disabled on the PSP for debugging purposes (I don't know if the PSP needs them at all, since it's using multitasking based on delays(a delay will cause the current thread to suspend and another to activate, defeating the purpose of locks, since locked parts will never use delays during it's execution?)).

I don't know if the Play/Stop keys will work on any keyboard, since they use the keyboard's scancodes directly (since SDL (the first version) doesn't seem to support them directly). Anyone can tell me if other keyboards work as well?

This is my latest build of my emulator:

- Upgraded project to Visual C++ 2015 (Visual Studio 2015), SDL and SDL_gfx also rebuilt with the toolchain.
- Fixed bug in VGA text rendering (inline functions wouldn't compile).

I've been busy fixing the CPU instructions using the 80186 testsuite (It's found here: http://forum.osdev.org/viewtopic.php?f=13&t=23739&start=15 . The post by Artlav has the link with the .zip file containing the testsuite). According to the testsuite all instructions work as they're supposed to (the result files match the memory after execution of the test files are completed). This is my latest build with all the bugfixes:

For some reason MS-DOS 3.30 still refuses to boot. The CPU seems to be working fine? Is the emulated hardware at fault here? I also notice in my floppy disk controller log, that it keeps re-reading the same sectors over and over again (sectors 58@CHS 1,1,5 to sector 71@CHS 1,1,18). Afaik it's supposed to read up to this point, or is it an error in my FDC emulation?

peterferrie wrote:

I'll have to investigate later what you're seeing. However, if you see reads to segment 0x70 while running from segment 0x70, t […]
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I'll have to investigate later what you're seeing. However, if you see reads to segment 0x70 while running from segment 0x70, then that's your problem.
These are the reads that you should see:
9ea0:0 (9 sectors)
690:0 (6)
690:c00 (0x12)
690:3000 (0x12)
690:5400 (0x11)
986:10 (1)
b72:10 (1)
b72:10 (1)
b51:10 (1)
c8b:0 (1)
c8b:200 (0x12)
c8b:2600 (0x12)
c8b:4a00 (0x0c)
b30:10 (1)

It's currently running until the 690:5400 (0x11) part.

This is what I'm getting atm:

19ee0:0 (9 sectors)
2690:0 (6)
3690:c00 (0x12)
4690:3000 (0x12)
5690:5400 (0x11)

Anyone can tell me what's going wrong here?

Latest version:

Also, can you tell me what each of those reads is supposed to be (what each block read actually is, like first 3 sectors of IO.SYS, reset of IO.SYS, nTh sector of MSDOS.SYS, COMMAND.COM, FAT entry etc.)?

These are the last commands executed before crashing (calling the MS-DOS 21h handler, which points to a NULL vector (start executing 0000:0000):

10:02:39:95.9.0005: 0256:7239 (FC)CLD
2
30:02:39:95.9.0016: Registers:
4
50:02:39:95.9.0028: AX: 9D3D, BX: 0070, CX: 0000, DX: A000
6
70:02:39:95.9.0041: CS: 0256, DS: 0070, ES: 0256, SS: 9DFD
8
90:02:39:95.9.0053: SP: 096F, BP: 0005, SI: 016E, DI: A000
10
110:02:39:95.9.0063: IP: 7239, FLAGS: F682
12
130:02:39:95.9.0087: FLAGSINFO:c1p0a0zStIDo1111
14
15
16
170:02:39:95.9.0354: Writing to memory: 00001D1E=3D (=)
18
190:02:39:95.9.0368: Writing to memory: 00001D1F=9D ()
20
210:02:39:95.9.0384: 0256:723A (A31E16)MOVW [DS:161E],AX
22
230:02:39:95.9.0393: Registers:
24
250:02:39:95.9.0405: AX: 9D3D, BX: 0070, CX: 0000, DX: A000
26
270:02:39:95.9.0417: CS: 0256, DS: 0070, ES: 0256, SS: 9DFD
28
290:02:39:95.9.0430: SP: 096F, BP: 0005, SI: 016E, DI: A000
30
310:02:39:95.9.0440: IP: 723A, FLAGS: F282
32
330:02:39:95.9.0465: FLAGSINFO:c1p0a0zStIdo1111
34
35
36
370:02:39:95.9.0731: Writing to memory: 0009E93D=40 (@)
38
390:02:39:95.9.0745: Writing to memory: 0009E93E=72 (r)
40
410:02:39:95.9.0762: 0256:723D (E8A6F5)CALL 67E6
42
430:02:39:95.9.0770: Registers:
44
450:02:39:95.9.0783: AX: 9D3D, BX: 0070, CX: 0000, DX: A000
46
470:02:39:95.9.0795: CS: 0256, DS: 0070, ES: 0256, SS: 9DFD
48
490:02:39:95.9.0807: SP: 096F, BP: 0005, SI: 016E, DI: A000
50
510:02:39:95.9.0818: IP: 723D, FLAGS: F282
52
530:02:39:95.9.0875: FLAGSINFO:c1p0a0zStIdo1111
54
55
56
570:02:39:96.0.0245: 0256:67E6 (BAB202)MOVW DX, 02B2
58
590:02:39:96.0.0255: Registers:
60

610:02:39:96.0.0267: AX: 9D3D, BX: 0070, CX: 0000, DX: A000
62
630:02:39:96.0.0280: CS: 0256, DS: 0070, ES: 0256, SS: 9DFD
64
650:02:39:96.0.0291: SP: 096D, BP: 0005, SI: 016E, DI: A000
66
670:02:39:96.0.0302: IP: 67E6, FLAGS: F282
68
690:02:39:96.0.0326: FLAGSINFO:c1p0a0zStIdo1111
70
71
72
730:02:39:96.0.0598: 0256:67E9 (B82225)MOVW AX, 2522
74
750:02:39:96.0.0609: Registers:
76
770:02:39:96.0.0621: AX: 9D3D, BX: 0070, CX: 0000, DX: 02B2
78
790:02:39:96.0.0633: CS: 0256, DS: 0070, ES: 0256, SS: 9DFD
80
810:02:39:96.0.0646: SP: 096D, BP: 0005, SI: 016E, DI: A000
82
830:02:39:96.0.0656: IP: 67E9, FLAGS: F282
84
850:02:39:96.0.0680: FLAGSINFO:c1p0a0zStIdo1111
86
87
88
890:02:39:96.0.0967: Writing to memory: 0000070A=B2 (²)
90
910:02:39:96.0.0981: Writing to memory: 0000070B=02 ()
92
930:02:39:96.0.0993: ModR/M address: 0070:000A=0000070A
94
950:02:39:96.1.0009: 0256:67EC (89160A00)MOVW [DS:000A],DX
96
970:02:39:96.1.0018: Registers:
98
990:02:39:96.1.0031: AX: 2522, BX: 0070, CX: 0000, DX: 02B2
100
1010:02:39:96.1.0043: CS: 0256, DS: 0070, ES: 0256, SS: 9DFD
102
1030:02:39:96.1.0055: SP: 096D, BP: 0005, SI: 016E, DI: A000
104
1050:02:39:96.1.0065: IP: 67EC, FLAGS: F282
106
1070:02:39:96.1.0090: FLAGSINFO:c1p0a0zStIdo1111
108
109
110
1110:02:39:96.1.0368: Writing to memory: 0000070C=70 (p)
112
1130:02:39:96.1.0382: Writing to memory: 0000070D=00 ( )
114
1150:02:39:96.1.0394: ModR/M address: 0070:000C=0000070C
116
1170:02:39:96.1.0410: 0256:67F0 (8C1E0C00)MOVW [DS:000C],DS
118
1190:02:39:96.1.0419: Registers:
120
1210:02:39:96.1.0430: AX: 2522, BX: 0070, CX: 0000, DX: 02B2
122
1230:02:39:96.1.0538: CS: 0256, DS: 0070, ES: 0256, SS: 9DFD
124
1250:02:39:96.1.0550: SP: 096D, BP: 0005, SI: 016E, DI: A000
126
1270:02:39:96.1.0561: IP: 67F0, FLAGS: F282
128
1290:02:39:96.1.0585: FLAGSINFO:c1p0a0zStIdo1111
130
131
132
1330:02:39:96.1.0892: Writing to memory: 0009E93B=82 (‚)
134
1350:02:39:96.1.0906: Writing to memory: 0009E93C=F2 (ò)
136
1370:02:39:96.1.0918: Writing to memory: 0009E939=56 (V)
138
1390:02:39:96.1.0929: Writing to memory: 0009E93A=02 ()
140
1410:02:39:96.1.0941: Writing to memory: 0009E937=F6 (ö)
142
1430:02:39:96.1.0952: Writing to memory: 0009E938=67 (g)
144
1450:02:39:96.1.0964: Read from memory: 00000084=00 ( )
146
1470:02:39:96.1.0975: Read from memory: 00000085=00 ( )
148
1490:02:39:96.1.0986: Read from memory: 00000086=00 ( )
150
1510:02:39:96.1.0998: Read from memory: 00000087=00 ( )
152
1530:02:39:96.2.0012: 0256:67F4 (CD21)INT 21
154
1550:02:39:96.2.0022: Registers:
156
1570:02:39:96.2.0034: AX: 2522, BX: 0070, CX: 0000, DX: 02B2
158
1590:02:39:96.2.0046: CS: 0256, DS: 0070, ES: 0256, SS: 9DFD
160
1610:02:39:96.2.0058: SP: 096D, BP: 0005, SI: 016E, DI: A000
162
1630:02:39:96.2.0069: IP: 67F4, FLAGS: F282
164
1650:02:39:96.2.0093: FLAGSINFO:c1p0a0zStIdo1111

Anyone knows why there is no MS-DOS INT 21h vector installed?

I'll take a look soon.

This is what I've found out so far (comparing it to the MS-DOS 3.30a source code):

048D:07F1=IO.SYS start
048D:08F4=SYSINIT in IO.SYS
9DFD:0942=SYSIN in IO.SYS
9DFD:0955=Move DOS to segment 256(64k bytes) using REP MOVSW.
9DFD:096A=CALL MSDOS ;CALL DOSINIT

Sector #33=IO.SYS first sector => DMA address 700 hex (segment 70). verified.
Sector #84(-89)=MSDOS.SYS first sector=> DMA address 6900 hex (segment 690) for 6 sectors. verified.
Sector #90(-107)=MSDOS.SYS second block => DMA address 7500 (segment 750) for 18 sectors.
Sector #108(-125)=MSDOS.SYS third block => DMA address 9900 (segment 990) for 18 sectors.
Sector #126(-142)=MSDOS.SYS final block => DMA address BD00 (segment BD0) for 17 sectors.

Is this correct? Can you give me information on the rest of the list you gave? (All numbers are 0 based, except the 6, 18 and 17 sectors and 64k bytes, which are 1 based).

This is my latest build:

I've fixed the errors in the floppy disk controller. Also added either third mouse button OR both mouse buttons pressed to trap mouse and enable a new Direct Mode: this allows you to enter input using the normal keyboard, instead of the old PSP compatible mode (Windows only).

MS-DOS 3.3 and 5.0 are booting now. 6.22 hangs when trying to detect the CDROM drive (there is no ATA nor CDROM emulation implemented yet). The command prompt also works.