What is best alternative?

[daydreamer]

If I have x and Y coordinates.  variables Stored in fixed point 16:16 so I get smooth movement, final fetch upper half for drawing? What is best?
Mov zx?
Mov +shift?
Push /pop?
Packed expand words to dwords?

[hutch--]

Depends on how fast you want to access the data, 2 x 16 bit is smaller but you have to extract the data but 2 x 32 bit are faster access in the decoding. Effectively splitting a single value into 2 parts is expensive time wise. If you want them as 16 bit values, store them sequentially as 16 bit values in an array.

[daydreamer]

Depends on how fast you want to access the data, 2 x 16 bit is smaller but you have to extract the data but 2 x 32 bit are faster access in the decoding. Effectively splitting a single value into 2 parts is expensive time wise. If you want them as 16 bit values, store them sequentially as 16 bit values in an array.

could as well go 64bit 32:32 must be most effective with many physics+control code ending in cache xpos,ypos in registers and use only upper 32bit part right before invoke imagedrawing?

[felipe]

I belive that in a game you would be updating the position of a game player a lot, so putting those coordinates in registers will be wise. Now, if you code in 64 bits, you have more registers to use, you can still use a 16 bit register part, even in those registers that couldn't do that before, as esi o edi. 

[jj2007]

you can still use a 16 bit register part, even in those registers that couldn't do that before, as esi o edi. 

Code Select Expand

include \masm32\MasmBasic\MasmBasic.inc
  Init
  mov edi, 11111111h
  mov di, 2222h
  deb 4, "Test", x:edi
EndOfCode

Output: Test    x:edi           11112222

[daydreamer]

I belive that in a game you would be updating the position of a game player a lot, so putting those coordinates in registers will be wise. Now, if you code in 64 bits, you have more registers to use, you can still use a 16 bit register part, even in those registers that couldn't do that before, as esi o edi. 

place everything in the same PROC with GetDC/ReleaseDC,64bit registers would have advantage of fast 32:32 bit physics together with invokes takes arguments from registers

actually I update coordinates inside fast timer that has freqency so it fits ca 30fps,a secondary slow timer that spawns/respawns objects that been destroyed
dont know how much faster it would go,if I do packed physics

[TouEnMasm]

If I have x and Y coordinates.  variables Stored in fixed point 16:16 so I get smooth movement, final fetch upper half for drawing? What is best?
Mov zx?
Mov +shift?
Push /pop?
Packed expand words to dwords?

Best way to solve this is to put it in a c program ,use /Ox and /FA,you get an asm who give you the best soluce.

[felipe]

you can still use a 16 bit register part, even in those registers that couldn't do that before, as esi o edi. 

Code Select Expand

include \masm32\MasmBasic\MasmBasic.inc
  Init
  mov edi, 11111111h
  mov di, 2222h
  deb 4, "Test", x:edi
EndOfCode

Output: Test    x:edi           11112222

You are absolutly right, how can the memory trick me after so much time without coding anything...My statement above should say 8 bit register part, which is not even in the question-topic...

Shame on me, btw thanks jj you have been very instructive as in other times. 

[jj2007]

You are absolutly right, how can the memory trick me after so much time without coding anything...My statement above should say 8 bit register part, which is not even in the question-topic...

Shame on me, btw thanks jj you have been very instructive as in other times. 

My pleasure, Felipe. Actually, I wasn't sure myself, as I have never used mov di, ... - so I tested it and it works

[daydreamer]

You are absolutly right, how can the memory trick me after so much time without coding anything...My statement above should say 8 bit register part, which is not even in the question-topic...

Shame on me, btw thanks jj you have been very instructive as in other times. 

My pleasure, Felipe. Actually, I wasn't sure myself, as I have never used mov di, ... - so I tested it and it works

would be nice to know 64bit choose of register usage,why do my compiler choose R9D(32bit) to use in a loop?
@Toutenmasm
offcourse I try that,but I doubt C compiler know the intention of use fixed point optimizations

[hutch--]

Magnus,

The Microsoft ABI (application binary interface) controls the registers that are used for different purposes. I think from memory that there is a list in the 64 bit MASM sub forum.

[jj2007]

Hutch,

I tried searching for it with abi rax rcx rdx r8 r9 scratch registers - 0 hits. So I took away the "abi" and tried again but was greeted with Your last search was less than 30 seconds ago. Please try again later.

Is that a setting against bots? For human search it makes little sense...

[hutch--]

> Is that a setting against bots?

Yes.

http://masm32.com/board/index.php?topic=6177.0

[jj2007]

Can you switch it off for members?

P.S.: I waited long enough and found your post titled Ray Chen on Win64, which explains register use in detail

[hutch--]

No, its there to stop bot floods.