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made reservation (MMU page lock) of BaS memory region (last megabyte of RAM) system independent

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Markus Fröschle
2013-10-31 06:34:40 +00:00
parent 9e8811876e
commit 48e0261f18
1 changed files with 6 additions and 5 deletions
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11
BaS_gcc/sources/mmu.S
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@@ -164,7 +164,8 @@ _mmu_init:
// 00f0'0000 locked
// this maps virtual 0x00F0'0000 - 0x00FF'FFFF to physical 0xFFF0'0000 - 0xFFFF'FFFF effectively making I/O area
// accesses ST-compatible (just the same what Atari made for TT and Falcon)
// accesses ST-compatible (just the same what Atari made for TT and Falcon). This does not get mapped for the
// m5484LITE boards which enables us to later act on I/O access attempts during a page miss exception
#ifdef MACHINE_FIREBEE
move.l #0x00f00000|std_mmutr,d0
move.l #0xfff00000|nocache_precise_mmudr|MCF_MMU_MMUDR_LK,d1
@@ -174,16 +175,16 @@ _mmu_init:
move.l d3,MCF_MMU_MMUOR // mapped to ffffxxx, precise,
#endif /* MACHINE_FIREBEE */
#ifdef MACHINE_FIREBEE
// 1ff0'0000 locked
// maps virtual 0x1FF0'0000 - 0x1FFF'FFFF to the same physical address
move.l #0x1FF00000|std_mmutr,d0 // last megabyte of physical RAM. Reserved for BaS
move.l #0x1FF00000|copyback_mmudr|MCF_MMU_MMUDR_LK,d1
move.l #(SDRAM_START + SDRAM_SIZE - 0x100000) | std_mmutr, d0 // last MB of physical RAM reserved for BaS
// move.l #0x1FF00000|std_mmutr,d0 // last megabyte of physical RAM. Reserved for BaS
move.l #(SDRAM_START + SDRAM_SIZE - 0x100000) | copyback_mmudr | MCF_MMU_MMUDR_LK,d1
// move.l #0x1FF00000|copyback_mmudr|MCF_MMU_MMUDR_LK,d1
move.l d0,MCF_MMU_MMUTR
move.l d1,MCF_MMU_MMUDR
move.l d2,MCF_MMU_MMUOR // setzen data
move.l d3,MCF_MMU_MMUOR // setzen instr
#endif /* MACHINE_FIREBEE */
move.l (sp)+,d2 // Restore registers
move.l (sp)+,d3