Result of running IWYU (https://include-what-you-use.org/) and
applying most of the suggestions about unncessary includes and
forward declarations.
Was motivated by observing that <thread> was being included in
ppcopcodes.cpp even though it was unused (found while researching
the use of threads), but seems generally good to help with build
times and correctness.
Use explicit cast when converting large integer types to smaller integer types when it is known that the most significant bytes are not required.
For pcidevice, check the ROM file size before casting to int. We'll allow expansion ROM sizes up to 4MB but usually they are 64K, sometimes 128K, rarely 256K.
for machinefactory, change the type to size_t so that it can correctly get the size of files that are larger than 4GB; it already checks the file size is 4MB before we need to cast to uint32_t.
For floppyimg, check the image size before casting to int. For raw images, only allow files up to 2MB. For DiskCopy42 images, it already checks the file size, so do the cast after that.
Fixed an issue where TBR doesn't have full 64-bit range. The original calculation was 64 bit and ended with a ÷ 10^9. This means the max for the upper 32 bits is 2^32/10^9 = 4. The solution is to use a multiplication method that supports a 96 bit product. core/mathutils.h contains functions for that. TBR driving frequency is assumed to be less than 1 GHz. Some minor modification is required for future > 1 GHz support.
Fixed an issue where get-msecs-601 and get-msecs-60x were not returning the same value. RTC was being calculated using timebase frequency instead of nanosecond frequency. 601 uses RTC. 60x uses TBR. On a real Mac, a G3 CPU won't have a RTC and accessing RTC would cause an exception. This is not the case for dingusppc but I don't think that's a problem.
Fixed an issue where RTC was not being updated if only the upper 32 bits (seconds) was read.
Also simplified things by always updating the timestamp instead of only when the seconds changes.
Fixed an issue where the following would cause inconsistent results (tb in the left column would sometimes decrement instead of always incrementing):
2 0 do 2 0 do cr tb@ 8 u.r ." ." 8 u.r loop 2 0 do cr 12 spaces rtc@ 8 u.r ." ." 8 u.r loop 2 0 do cr tb@ 8 u.r ." ." 8 u.r space rtc@ 8 u.r ." ." 8 u.r loop loop
RTC and TBR could not be used simultaneously because they are both incremented by an amount based on the last time stamp but that time stamp can be changed by accessing either RTC or TBR. The solution is to have a different time stamp for each.
Fixed a typo that caused rtc@ to always return 0 for the upper 32 bits (represents seconds).
The problem could cause the following to hang on Power Mac 7500:
cr 2000 0 do get-msecs u. 1 ms loop
