[fpc-devel] threadvar implementation

"Vinzent Höfler" JeLlyFish.software at gmx.net
Wed Aug 4 22:29:39 CEST 2010


Michael Schnell <mschnell at lumino.de>:

> I fail to understand what LEA is supposed to do if a (single) segment 
> register is given :(.

Ignoring it, because it is not part of the "effective address" which it is supposed to calculate?

<http://www.intel.com/software/products/documentation/vlin/mergedprojects/analyzer_ec/mergedprojects/reference_olh/mergedprojects/instructions/instruct32_hh/vc150.htm>:

|"The source operand is a memory address (offset part)"
                                          ^^^^^^^^^^^

Says that only the offset is used.

|"specified with one of the processors addressing modes"
                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Obviously this includes "segmented addressing modes" with segment (or descriptor) prefixes.

So I don't know why you seem so confused. After all, it's x86. See signature. :)


Vinzent.

-- 
Intel CPUs are not defective, they just act that way.
        -- Henry Spencer

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