Re: Behaviour of reg32 with SMSW/SLDT/STR?
Posted on 2019-03-07, 18:59
crazyc wrote: What "undefined" means you'd have to test on a real machine. On 486dx: SMSW stores CR0 STR, SLDT, MOV SR: upper 16 bits are cleared
Re: Windows 3.0 triple faults within first Paging VxD call?
Posted on 2018-08-10, 16:37
0028:802000b0 8B 75 E4 mov esi,dword ss:[ebp-1c] See what is the value in memory of ss:[ebp-1c] (30:80013294), maybe you're loading the wrong data. Check if SS is correctly set, maybe it should not be 0x30? Verify that the value of EBP: 800132b0 is correct. The possibilities are countless...
Re: Software for verifying x86 protected mode features(80286/80386)?
Posted on 2018-05-24, 15:48
unless you want to test read/write faults on EVERY single opcode? No that would be unfeasable. At this point it's more like a reminder to add a test for XLAT, which is missing. But you're right it won't probably detect your particular bug. The goal is to test as much as possible for the correct …
Re: Software for verifying x86 protected mode features(80286/80386)?
Posted on 2018-05-23, 14:51
superfury wrote: It's the XLAT instructions(both 16-bit and 32-bit versions) that were faulty: it was checking memory against a write(for the memory operand) instead of a proper read. Adding this as well to the test386.asm issue tracker.
Re: Software for verifying x86 protected mode features(80286/80386)?
Posted on 2018-05-22, 13:42
You could also try to run some demanding protected mode DOS game, like Pinball Illusions. Look at what that game throws at me when I try to run it with my emu: https://github.com/barotto/IBMulator/issues/32
Re: Software for verifying x86 protected mode features(80286/80386)?
Posted on 2018-05-22, 13:29
Hottobar's test386.asm testsuite already checks out 100%. Edit: Another code bug revealed with the POP ES instruction: it wasn't using the operand size to perform the 16-bit POP. So it was always increasing/decreasing (E)SP with 2 instead of the proper 4. I know test386.asm does not test all the …
Re: test386.asm CPU tester
Posted on 2017-11-20, 18:00
//According to IBMulator more like "According to DOSBox"... I've unashamedly copied AAA and AAS code straight from DOSBox, which is correct regarding the undefined flags for pre-pentium hw (for those opcodes anyway). EDIT: why do you modify ZF and SF at the end of the AAA procedure? FLAGW_ZF((REG_ …
Re: test386.asm CPU tester
Posted on 2017-11-19, 18:05
superfury wrote: Does IBMulator's output match real hardware(which means incorrect manuals)? Now it does 😀
Re: test386.asm CPU tester
Posted on 2017-11-19, 17:59
Nobody is bored enough to make task switching, security and vm86 tests I guess :) It's not so much about boredom, it's more like being able to define a meaningful test and to find the time to implement it, while having a very good understanding of the matter, ofc. :) Anyway, I've finally found the …
Re: test386.asm CPU tester
Posted on 2017-11-03, 18:36
I know, but I assume that if the data size is constant(e.g. 64-bit integer, 32-bit integer, 16-bit integer, 8-bit integer), it shouldn't be a problem(e.g. uint_64 to int_64 and vise-versa)? The only thing that effectively changes is the sign bit becoming a negative value of itself, assuming C/C++ …
Re: test386.asm CPU tester
Posted on 2017-11-03, 17:48
Edit: Having fixed this, it now continues on towards the other tests:D Congratulations! :D Can you see what's exactly going wrong? Search for OP0FXX or OPXX for the opcode emulation itself(OP6B, OP69, OPF6, OPF7 and OPD*). I quickly read CPU_OP6B(), I didn't find the bug but here's a couple of …
Re: test386.asm CPU tester
Posted on 2017-10-30, 17:40
vladstamate wrote: Man, the encoding for that is crazy. x86 is crazy. 🤣
Re: test386.asm CPU tester
Posted on 2017-10-30, 17:20
I'm just asking to be sure: to the CPU, does a 2-operand opcode 69/6B(IMUL r16,imm8/16) even exist? Or does it always decode to 3 operands, with r/m and immediate being multiplied and stored into the reg operand? 6B/69 are 3-operand only: 6B /r ib IMUL r16, r/m16, imm8 word register ← r/m16 ∗ sign- …
Re: test386.asm CPU tester
Posted on 2017-10-29, 16:03
There's something I notice about the test386.asm repository: it does seem to have a EE file(test386-EE-reference) for normal logs, but not another one for the logs for the undefined flags as well(the TEST_UNDEF enabled test)? Test 0xE0 (undefined behaviours) depends on the CPU family. I didn't want …
Re: test386.asm CPU tester
Posted on 2017-10-29, 14:27
The old Intel dev manuals are wrong. The correct algorithm is reported in the current IA-32 Software Dev's Manual (Volume 2A). old_AL ← AL; old_CF ← CF; CF ← 0; IF (((AL AND 0FH) > 9) or AF = 1) THEN AL ← AL - 6; CF ← old_CF or (Borrow from AL ← AL − 6); AF ← 1; ELSE AF ← 0; FI; IF ((old_AL > 99H) …
Re: test386.asm CPU tester
Posted on 2017-10-29, 13:37
Here's the bug: Copy code to clipboard 1 else 2 { 3 FLAGW_CF(0); 4 }
Re: test386.asm CPU tester
Posted on 2017-10-28, 17:16
I opened an issue rather than forking the code because I haven't spent the time yet to understand how to add new tests by myself. I hope that's acceptable. I've updated test386.asm with a BCD undefined flags test (for the 80386 only though). I've also validated the flags values against a 386SX …
Re: test386.asm CPU tester
Posted on 2017-10-24, 17:16
The list file is unchanging, though(only if source code is changed in the testsuite, which is only the base constants and the additional logging code): test386.lst.zip The #DE handler moves a new EIP to the stack (0010:C20C), so that the iretd at 0010:C213 can return to a ret, instead of the div …
Re: Fastest DOS VLB Graphics card ever?
Posted on 2017-10-23, 16:37
The ARENA developers are known for pulling influences from Ultima Underworld and Dungeons & Dragons, which released the massive, open, but ultimately derivative, first-person RPG: "The Elder Scrolls: ARENA". The 3D engine however stands out completely from Ultima as it gave you the freedom to move …
Re: test386.asm CPU tester
Posted on 2017-10-23, 16:02
Strange: I only see UniPCemu emitting one 32-bit DIV instruction, which isn't overflowing or divide by 0? 0x245af920e27415a5 / 0x88776655 = 0x44332211 remainder 0. After the final IMUL32 D entry, it ends up at a interrupt-disabled HLT instruction? No DIV instruction is executed at all. test386_ …
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