projects / ceph.git / blame
| Commit | Line | Data |
|---|---|---|
| 7c673cae FG |
1 | GC on EWS4800 |
| 2 | ------------- | |
| 3 | ||
| 4 | 1. About EWS4800 | |
| 5 | EWS4800 is 32bit/64bit workstation. | |
| 6 | ||
| 7 | Vender: NEC Corporation | |
| 8 | OS: UX/4800 R9.* - R13.* (SystemV R4.2) | |
| 9 | CPU: R4000, R4400, R10000 (MIPS) | |
| 10 | ||
| 11 | 2. Compiler | |
| 12 | ||
| 13 | 32bit: | |
| 14 | Use ANSI C compiler. | |
| 15 | CC = /usr/abiccs/bin/cc | |
| 16 | ||
| 17 | 64bit: | |
| 18 | Use 64bit ANSI C compiler. | |
| 19 | CC = /usr/ccs64/bin/cc | |
| 20 | AR = /usr/ccs64/bin/ar | |
| 21 | ||
| 22 | 3. ELF file format | |
| 23 | *** Caution: The following infomation is empirical. *** | |
| 24 | ||
| 25 | 32bit: | |
| 26 | ELF file has an unique format. (See a.out(4) and end(3C).) | |
| 27 | ||
| 28 | &_start | |
| 29 | : text segment | |
| 30 | &etext | |
| 31 | DATASTART | |
| 32 | : data segment (initialized) | |
| 33 | &edata | |
| 34 | DATASTART2 | |
| 35 | : data segment (uninitialized) | |
| 36 | &end | |
| 37 | ||
| 38 | Here, DATASTART and DATASTART2 are macros of GC, and are defined as | |
| 39 | the following equations. (See include/private/gcconfig.h.) | |
| 40 | The algorithm for DATASTART is similar with the function | |
| 41 | GC_SysVGetDataStart() in os_dep.c. | |
| 42 | ||
| 43 | DATASTART = ((&etext + 0x3ffff) & ~0x3ffff) + (&etext & 0xffff) | |
| 44 | ||
| 45 | Dynamically linked: | |
| 46 | DATASTART2 = (&_gp + 0x8000 + 0x3ffff) & ~0x3ffff | |
| 47 | ||
| 48 | Statically linked: | |
| 49 | DATASTART2 = &edata | |
| 50 | ||
| 51 | GC has to check addresses both between DATASTART and &edata, and | |
| 52 | between DATASTART2 and &end. If a program accesses between &etext | |
| 53 | and DATASTART, or between &edata and DATASTART2, the segmentation | |
| 54 | error occurs and the program stops. | |
| 55 | ||
| 56 | If a program is statically linked, there is not a gap between | |
| 57 | &edata and DATASTART2. The global symbol &_DYNAMIC_LINKING is used | |
| 58 | for the detection. | |
| 59 | ||
| 60 | 64bit: | |
| 61 | ELF file has a simple format. (See end(3C).) | |
| 62 | ||
| 63 | _ftext | |
| 64 | : text segment | |
| 65 | _etext | |
| 66 | _fdata = DATASTART | |
| 67 | : data segment (initialized) | |
| 68 | _edata | |
| 69 | _fbss | |
| 70 | : data segment (uninitialized) | |
| 71 | _end = DATAEND | |
| 72 | ||
| 73 | -- | |
| 74 | Hironori SAKAMOTO <hsaka@mth.biglobe.ne.jp> | |
| 75 | ||
| 76 | ||
| 77 | When using the new "configure; make" build process, please | |
| 78 | run configure with the --disable-shared option. "Make check" does not | |
| 79 | yet pass with dynamic libraries. Ther reasons for that are not yet | |
| 80 | understood. (HB, paraphrasing message from Hironori SAKAMOTO.) | |
| 81 |