1.9 KiB
Overview
TRACE.COM takes an instruction log, as recorded by the PCjs Debugger's traceLog() function, and "plays" the instructions back on another machine DOS-compatible 8086 machine, verifying that:
- Results match the recorded results;
- Any "modified" flags match the recorded flags; and
- Any "unmodified" flags remain unmodified
The format of an instruction log entry is a series of lines (ASCII characters terminated by an LF), where each line looks like:
F000:EEFF SHL(0480,0002,F006) 1200,F006
specifically:
address, space, instruction, parenthesis, dst operand, comma, src operand, comma,
input flags, parenthesis, space, result, comma, and output flags
WARNING: For the shift and rotate tests to pass on a real x86 CPU, we either have to distinguish between single-bit shifts and multi-bit shifts (because the latter leaves PS_OF in an "undefined" state), or we have to ignore PS_OF altogether. For now, I'm specifying PS_ALL_BUT_OF for those instructions, even though we'll be missing OVERFLOW validation for all single-bit shifts and rotates.
Operation
To load TRACE.COM and TRACE.TXT onto a virtual disk image that PCjs can access, you can add an "automount" setting to your PCjs configuration that will dynamically generate a fresh disk image every time the machine is loaded, via the DiskDump API. This is useful when you're constantly generating new test results:
<fdc id="fdcNEC" automount='{B:{name:"Trace Tests",path:"/tests/pc/trace/trace.com;trace.txt"}}'/>
Alternatively, if you want to run the tests in another virtual PC environment (eg, VMware Fusion), you can create an IMG disk image from a directory using DiskDump's command-line interface:
cd ~/Sites/pcjs/tests/pc
node ~/Sites/pcjs/modules/diskdump/bin/diskdump --dir=trace --format=img --output=trace.img
OS X users can also create an ISO image like so:
hdiutil makehybrid -o ~/Sites/pcjs/tests/pc/trace.iso ~/Sites/pcjs/tests/pc/trace -iso -joliet