Structure alignment

[sinsi]

Within a structure, items should be naturally aligned

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structure1 struct
  v32_1    dd ? ;offset 0
           dd ? ;offset 4, padding
  v64_1    dq ? ;offset 8
structure1 ends


Automatically aligned?

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structure1 struct 8
  v32_1    dd ? ;offset 0
  v64_1    dq ? ;offset 8
structure1 ends


Should a structure pad the end to align 8?

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structure2 struct 8
  v64_1    dq ? ;offset 0
  v32_1    dd ? ;offset 8
           dd ?
structure2 ends


Does alignment only matter within a structure?

Code Select Expand


var1  dd ?          ;.data? offset 0
str2  structure2 <> ;.data? offset 4 - str2.v64_1 not aligned to 8 - doesn't matter?


[nidud]

deleted

[sinsi]

So memory alignment isn't required but would be more efficient.
Does the -Zp[n] switch override the structure definition?

Would a nested structure need alignment within the main structure?


Thanks for your time.

[jj2007]

I agree with Nidud that the Zp switch is the way to go. -Zp8 for 64-bit code, to be precise. Everything else is a can of worms.