73 lines
1.2 KiB
NASM
73 lines
1.2 KiB
NASM
; FXF relocation routines
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; relocate a FXF binary
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; inputs:
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; r0: pointer to memory buffer containing a FXF binary
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; outputs:
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; r0: relocation address
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fxf_reloc:
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push r1
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push r2
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push r3
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push r4
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push r5
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; calculate relocation address
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mov r5, r0
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add r5, FXF_CODE_PTR
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mov r5, [r5]
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add r5, r0
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; get the number of entries in the reloc table
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mov r1, r0
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add r1, FXF_RELOC_SIZE
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mov r1, [r1]
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div r1, 4
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mov r31, r1
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cmp r31, 0
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ifz mov r0, r5
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ifz pop r5
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ifz pop r4
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ifz pop r3
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ifz pop r2
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ifz pop r1
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ifz ret
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; get the pointer to the table
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mov r1, r0
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add r1, FXF_RELOC_PTR
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mov r1, [r1]
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add r1, r0
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; get the pointer to the code
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mov r2, r0
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add r2, FXF_CODE_PTR
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mov r2, [r2]
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add r2, r0
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; loop over the reloc table entries and relocate the code
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fxf_reloc_loop:
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; get the reloc table entry
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mov r3, [r1]
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; point to the location in the code
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mov r4, r2
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add r4, r3
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; relocate
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add [r4], r5
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; increment the reloc table pointer
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add r1, 4
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loop fxf_reloc_loop
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; return relocation address
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mov r0, r5
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pop r5
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pop r4
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pop r3
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pop r2
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pop r1
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ret
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