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| author | Joel Sherrill <joel.sherrill@OARcorp.com> | 1996-05-01 15:25:33 +0000 |
|---|---|---|
| committer | Joel Sherrill <joel.sherrill@OARcorp.com> | 1996-05-01 15:25:33 +0000 |
| commit | 996a9cb4e2a7d2d9ae43b8e3eb531a81ccefe690 (patch) | |
| tree | 4d342614395f1c4fc7c3128a92212cef2e31e69c /c/src/lib/libbsp/m68k/gen68360/start | |
| parent | Updates from Eric Norum to use the mcpu32 flags and fix comments. (diff) | |
| download | rtems-996a9cb4e2a7d2d9ae43b8e3eb531a81ccefe690.tar.bz2 | |
Updates from Eric Norum.
Diffstat (limited to 'c/src/lib/libbsp/m68k/gen68360/start')
| -rw-r--r-- | c/src/lib/libbsp/m68k/gen68360/start/start360.s | 46 |
1 files changed, 29 insertions, 17 deletions
diff --git a/c/src/lib/libbsp/m68k/gen68360/start/start360.s b/c/src/lib/libbsp/m68k/gen68360/start/start360.s index b546e72406..2c4ed13066 100644 --- a/c/src/lib/libbsp/m68k/gen68360/start/start360.s +++ b/c/src/lib/libbsp/m68k/gen68360/start/start360.s @@ -298,11 +298,11 @@ uhoh: nop | Leave spot for breakpoint bra.s uhoh | Stuck forever /* - * Place the low-order 3 octets of the board's - * ethernet address at a `well-known' location. + * Place the low-order 3 octets of the board's ethernet address at + * a `well-known' fixed location relative to the beginning of ROM. */ .align 2 -| .long ETHERNET_ADDRESS | 08: Low-order 3 octets + .long ETHERNET_ADDRESS | Low-order 3 octets of ethernet address /* * Initial PC @@ -347,24 +347,36 @@ start: */ jmp SYM(_Init68360) | Start C code (which never returns) - /* - * Clear BSS, set up real stack, initialize heap, start C program - * Assume that BSS size is a multiple of 4. - * FIXME: The zero-loop should be changed to put the CPU into loop-mode. - * FIXME: PROM-based systems will have to copy data segment to RAM here + * Copy DATA segment, clear BSS segment, set up real stack, + * initialize heap, start C program. + * Assume that DATA and BSS sizes are multiples of 4. */ - PUBLIC (_ClearBSSAndStart) -SYM(_ClearBSSAndStart): - movel #clear_start,a0 - movel #clear_end,a1 - clrl d0 - bras ZEROLOOPTEST + PUBLIC (_CopyDataClearBSSAndStart) +SYM(_CopyDataClearBSSAndStart): + lea copy_start,a0 | Get start of DATA in RAM + lea SYM(etext),a2 | Get start of DATA in ROM + cmpl a0,a2 | Are they the same? + beq.s NOCOPY | Yes, no copy necessary + lea copy_end,a1 | Get end of DATA in RAM + bra.s COPYLOOPTEST | Branch into copy loop +COPYLOOP: + movel a2@+,a0@+ | Copy word from ROM to RAM +COPYLOOPTEST: + cmpl a1,a0 | Done? + bcs.s COPYLOOP | No, skip +NOCOPY: + + lea clear_start,a0 | Get start of BSS + lea clear_end,a1 | Get end of BSS + clrl d0 | Value to set + bra.s ZEROLOOPTEST | Branch into clear loop ZEROLOOP: - movel d0,a0@+ + movel d0,a0@+ | Clear a word ZEROLOOPTEST: - cmpl a1,a0 - bcs ZEROLOOP + cmpl a1,a0 | Done? + bcs.s ZEROLOOP | No, skip + movel #stack_init,a7 | set master stack pointer movel d0,a7@- | environp movel d0,a7@- | argv |