Martin Michelsen
62 lines
1.3 KiB
ArmAsm
62 lines
1.3 KiB
ArmAsm
.versions PPC
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start:
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mflr r7
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# If this patch has already been run, then the opcode that led here will not be bctrl (4E800421). In that case, do
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# nothing.
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lis r3, 0x4E80
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ori r3, r3, 0x0421
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lwz r4, [r7 - 4]
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cmp r3, r4
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beq apply_patch
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blr
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apply_patch:
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bl patch_end
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.offsetof patch
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.offsetof patch_end
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patch:
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mfctr r6
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mr r3, r6
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li r4, 0x7C00
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.include FlushCachedCode
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mtctr r6
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bctr
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patch_end:
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mflr r4
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addi r4, r4, 8
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lwz r3, [r4 - 8]
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lwz r5, [r4 - 4]
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sub r5, r5, r3
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lis r3, 0x8000
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ori r3, r3, 0x01BC
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mr r6, r3
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# At this point:
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# r3 = destination location (overwritten by CopyCode)
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# r4 = patch src data (overwritten by CopyCode)
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# r5 = patch size in bytes (overwritten by CopyCode)
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# r6 = destination location
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# r7 = saved LR
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.include CopyCode
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setup_branch:
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# Replace the bctrl opcode that led to this call with a bl opcode that leads to the copied patch code
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subi r3, r7, 4
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sub r4, r6, r3
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rlwinm r4, r4, 0, 6, 31
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oris r4, r4, 0x4800
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ori r4, r4, 0x0001
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stw [r3], r4
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dcbst r0, r3
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sync
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icbi r0, r3
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isync
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# Return the address that the patch was copied to
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mr r3, r6
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mtlr r7
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blr
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