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barotto / test386.asm

x86 CPU tester for emulators
GNU General Public License v3.0
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Stuff to look into #9

Open barotto opened 5 years ago

barotto commented 5 years ago

From #5 (@superfury)

I notice something, looking through the arithmetic(EE) tests: you're not testing all memory-related cases of the tested opcodes. Opcodes 00-3F only seems to test for memory as the destination(being read and written to), not the source(only being read from, destination being the register of the modr/m(opcodes ending in the 0 and 1 nibbles)). Opcodes 80-83 don't test the memory cases at all. The same for opcodes F6 and F7, as well as FE&FF INC/DEC(but for register operands). 0FAF isn't tested for memory operands. And F6/F7 (I)DIV don't verify reads from memory operands.

Also C and D shift/rotate instructions aren't tested for memory operands.

Edit: Just found and fixed a bug in the PUSH/POP SegReg instructions that caused it to increase/decrease virtual ESP(for protection checks) by 2 instead of 4 while verifying against 16-bit memory accesses. As well as fixing 16-bit SIDT/SGDT to properly fill the final byte with 0x00(386+) or 0xFF(286+). Edit: The 80386 also seems to have had errors in loading the IDTR/GDTR with LIDT/LGDT when the operand size was 16-bit, causing it to load the highest byte(92h in the MSB of the IDTR/GDTR) incorrectly.

I eventually found some bugs with the BSF and BSR instructions(ZF flag updated incorrectly(for the r/m16/32 value being 1) and the reg value not being written into the register)

superfury commented 5 years ago

I've added those instructions to UniPCemu's testsuite(which requires verification by looking at the log, nothing automated in it). They seem to produce correct results :D

So UniPCemu doesn't seem to have problems with those instructions(didn't test anything like paging and protection etc. through). Also, it just tests the generic subset of those instructions(with reads from memory using mul/div and writes/reads with all others). https://bitbucket.org/superfury/unipcemu/src/a66465b37988aaef7bcb0a908d8199e400d09794/UniPCemu/assembly/?at=master

superfury commented 5 years ago

Any ideas on implementing the remainder of tests with protected mode interrupts and tasks?