| 1 | # |
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| 2 | # $Id$ |
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| 3 | # |
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| 4 | |
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| 5 | There are various issues regarding this port: |
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| 6 | |
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| 7 | |
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| 8 | |
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| 9 | 1) Legal |
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| 10 | |
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| 11 | This port is written by Andrew Bray <andy@i-cubed.co.uk>, and |
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| 12 | is copyright 1995 i-cubed ltd. |
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| 13 | |
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| 14 | This port was later updated by Joel Sherrill <joel@OARcorp.com> |
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| 15 | to test the support for the PPC603, PPC603e, and MPC604. This |
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| 16 | was tested on the PowerPC simulator PSIM and a VMEbus single board |
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| 17 | computer. |
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| 18 | |
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| 19 | 2) CPU support. |
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| 20 | |
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| 21 | This release fully supports the PPC403GA, PPC403GB, PPC603, PPC603e, |
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| 22 | MPC604, MPC750, and numerous MPC8xx processors. A good faith attempt |
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| 23 | has been made to include support other models based upon available |
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| 24 | documentation including the MPC5xx. There are two interrupt structures |
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| 25 | supported by the PowerPC port. The newer structure is supported by |
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| 26 | all the MPC750 and MPC604 BSPs. This structure is required to use |
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| 27 | the RDBG remote debugging support. |
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| 28 | |
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| 29 | This port was originally written and tested on the PPC403GA (using |
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| 30 | software floating point). Current ports are tested primarily on |
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| 31 | 60x CPUs using the PowerPC simulator PSIM. |
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| 32 | |
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| 33 | Andrew Bray received assistance during the initial porting effort |
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| 34 | from IBM and Blue Micro and we would like to gratefully acknowledge |
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| 35 | that help. |
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| 36 | |
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| 37 | The support for the PPC602 processor is incomplete as only sketchy |
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| 38 | data is currently available. Perhaps this model has been dropped. |
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| 39 | |
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| 40 | 3) Application Binary Interface |
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| 41 | |
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| 42 | In the context of RTEMS, the ABI is of interest for the following |
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| 43 | aspects: |
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| 44 | |
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| 45 | a) Register usage. Which registers are used to provide static variable |
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| 46 | linkage, stack pointer etc. |
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| 47 | |
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| 48 | b) Function calling convention. How parameters are passed, how function |
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| 49 | variables should be invoked, how values are returned, etc. |
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| 50 | |
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| 51 | c) Stack frame layout. |
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| 52 | |
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| 53 | I am aware of a number of ABIs for the PowerPC: |
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| 54 | |
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| 55 | a) The PowerOpen ABI. This is the original Power ABI used on the RS/6000. |
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| 56 | This is the only ABI supported by versions of GCC before 2.7.0. |
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| 57 | |
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| 58 | b) The SVR4 ABI. This is the ABI defined by SunSoft for the Solaris port |
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| 59 | to the PowerPC. |
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| 60 | |
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| 61 | c) The Embedded ABI. This is an embedded ABI for PowerPC use, which has no |
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| 62 | operating system interface defined. It is promoted by SunSoft, Motorola, |
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| 63 | and Cygnus Support. Cygnus are porting the GNU toolchain to this ABI. |
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| 64 | |
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| 65 | d) GCC 2.7.0. This compiler is partway along the road to supporting the EABI, |
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| 66 | but is currently halfway in between. |
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| 67 | |
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| 68 | This port was built and tested using the PowerOpen ABI, with the following |
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| 69 | caveat: we used an ELF assembler and linker. So some attention may be |
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| 70 | required on the assembler files to get them through a traditional (XCOFF) |
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| 71 | PowerOpen assembler. |
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| 72 | |
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| 73 | This port contains support for the other ABIs, but this may prove to be |
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| 74 | incomplete as it is untested. |
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| 75 | |
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| 76 | The RTEMS PowerPC port supports EABI as the primary ABI. The powerpc-rtems |
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| 77 | GNU toolset configuration is EABI. |
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| 78 | |
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| 79 | Andrew Bray, 4 December 1995 |
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| 80 | Joel Sherrill, 16 July 1997 |
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![[RTEMS Logo]](/images/logo.png){kind=logo}
