47bd0ef7a7
Do the conversion by calling .cif8 or .cuf8 in libem, as it was done before my commit1de1e8f. I used the inline conversion to experiment with the register allocator, which was too slow untilc5bb3be. Now that libem has the only copy of the code, move some comments and code changes there.
31 lines
791 B
ArmAsm
31 lines
791 B
ArmAsm
.sect .text; .sect .rom; .sect .data; .sect .bss
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.sect .text
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! Converts a 32-bit integer into a 64-bit double.
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!
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! Stack: ( int -- double )
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.define .cif8
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.cif8:
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! Conversion uses the pivot value
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! 1 << 52 = 0x4330 0000 0000 0000
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!
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! From signed integer i, we compute
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! ((1 << 52) + (1 << 31) + i) - ((1 << 52) + (1 << 31))
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lis r3, 0x4330
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stwu r3, -4(sp) ! make space for the double
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lwz r3, 4(sp)
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xoris r3, r3, 0x8000
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stw r3, 4(sp) ! flip sign bit to get (1 << 31) + i
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lfd f0, 0(sp) ! f0 = (1 << 52) + (1 << 31) + i
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lis r3, 0x8000
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stw r3, 4(sp)
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lfd f1, 0(sp) ! f1 = (1 << 52) + (1 << 31)
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fsub f0, f0, f1 ! finish conversion
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stfd f0, 0(sp) ! save value again...
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blr ! ...and return
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