From: George Koehler Date: Sat, 3 Dec 2016 22:17:44 +0000 (-0500) Subject: Write README files for osx386 and osxppc. X-Git-Url: https://git.ndcode.org/public/gitweb.cgi?a=commitdiff_plain;h=355cc06fff7bbf2590c39b5f1802f49cb490c02f;p=ack.git Write README files for osx386 and osxppc. --- diff --git a/plat/osx386/README b/plat/osx386/README new file mode 100644 index 000000000..8c34134ff --- /dev/null +++ b/plat/osx386/README @@ -0,0 +1,25 @@ +The osx386 platform +=================== + + ack -mosx386 ... + +This platform produces Mach-o executables for Intel Mac OS X. These +are 32-bit executables using our i386 code generator. + +See ../osxppc/README, because our osx386 platform has many of the same +limitations and bugs as our osxppc platform. + + +Bugs +---- + +Some programs can't read the tty after using job control to suspend +and resume the program (with ^Z and "fg" in bash). The read(2) system +call fails with EINTR. In ACK's stdio (in libc), the error is sticky, +so all reads fail. In Apple's stdio, the error is not sticky, and +only the next read fails. The EINTR seems to happen only on Intel Mac +OS X, and not on other platforms. + + +George Koehler +2016-12-03 diff --git a/plat/osxppc/README b/plat/osxppc/README new file mode 100644 index 000000000..dd9a4d49c --- /dev/null +++ b/plat/osxppc/README @@ -0,0 +1,110 @@ +The osxppc platform +=================== + + ack -mosxppc ... + +This platform produces Mach-o executables for PowerPC Mac OS X. You +can run them from the command line in the Terminal. + +You *can't* link to libraries from other compilers. These static +executables don't use the dynamic linker. They don't load Apple's +libraries, so they can't call Carbon or Cocoa. + +The executables use BSD system calls to interact with your Mac. Our +libsys provides only a few system calls, enough to run a few demo +programs, but not much else. Check the header files in ../osx/include +for the available system calls. + + +Bugs +---- + +ACK didn't run on Mac OS X when this platform was added. The only way +to run ack -mosxppc was as a cross compiler from another operating +system. + +ACK doesn't have 64-bit integers, but Mac OS X uses 64-bit integers in +its system calls. Our libsys converts between 32-bit and 64-bit +integers by setting the high bits to zero, or discarding the high +bits. This affects lseek() and stat(). They report the wrong values +for file sizes and offsets beyond 4 gigabytes. + +Our PowerPC code generator is new and probably has bugs. Its stack +layout and calling conventions are not compatible with other +compilers. It passes all function arguments on the stack, which is +slower than passing them in registers. + + +Example +------- +Compile something: + + ack -mosxppc -O6 -o paranoia examples/paranoia.c + +The executable has a symbol table. If you have Apple's Xcode, try + + nm -g paranoia # to list the global symbols + otool -hl paranoia # to check the Mach header and load commands + gdb paranoia # to debug it + +Within gdb, commands like "gdb main" and "gdb '.ret'" can disassemble +functions. Backtraces don't work, because our stack layout is not the +same as Apple's. + + +Other hints +----------- + +PowerPC Macs became obsolete after Apple's transition to Intel. Mac +OS X 10.5 Leopard was the last version to run on PowerPC. The older +Mac OS X 10.4 Tiger was the last version to include Classic for +running Mac OS 9 programs. Our ack -mosxppc began to produce +executables in 2016, about 7 years after Apple released Mac OS X 10.6 +Snow Leopard for Intel only. + +Apple's Xcode included tools like gcc and gdb. It also had manual +pages for some system calls, like getdirentries(2). Some system calls +are like FreeBSD, some are unique to OS X. If you want to learn how +to call write(2) or sigaction(2), then a manual page from another BSD +or Linux might be enough. + +Xcode 2.5 was the last version to run on Tiger. The "Xcode 2.5 +Developer Tools" were a 902.9 MB download from Apple. As of 2016, the +download required an Apple ID and was available at: + + https://developer.apple.com/download/more/ + +Older versions of Xcode came with Mac OS X. If your version of OS X +came with your Mac, /Applications/Installers might contain an Xcode +installer. If you upgraded OS X, your install DVD might have Xcode. + +The source code at https://opensource.apple.com/ might reveal more +about system calls. For 10.4.11.ppc, the kernel is in xnu-792.24.17, +and Libc is in Libc-391.2.10. These files might help: + + xnu*/bsd/kern/syscalls.master + master list of BSD system calls + xnu*/osfmk/kern/syscall_sw.c + master list of Mach traps + xnu*/bsd/kern/mach_loader.c + details about loading Mach-o executables + xnu*/bsd/dev/ppc/unix_signal.c + details about sending signals to processes + xnu*/bsd/sys/*.h + headers that Xcode installs as /usr/include/sys/*.h + xnu*/bsd/man/man2/*.2 + manual pages that Xcode installs as /usr/share/man/man2/*.2 + Libc*/ppc/sys/SYS.h + Libc*/ppc/sys/*.s + assembly code (in gas syntax) for making system calls + +The 10.4.11.ppc sources are wrong for Intel; use 10.4.11.x86 or 10.5 +or newer. 10.5 moved SYS.h to xnu*/libsyscall/custom/SYS.h + +The kernel maps a common page into every process, and Apple's Libc +uses the common page to speed up system calls like gettimeofday(2). +Our libsys does not use the common page. + + +George Koehler +2016-12-03