how to Fast Call cdecl api like sqlite3.dll?

[Schmidt]

...how to call cdecl_add by function VB_ADD(11,22)?

There is usually no need, to fumble around with ASM-Code (making your whole App a ticking time-bomb).

Especially not in cases, where the (__cdecl-)function you plan to call, has to perform:
- a whole lot of stuff internally (as e.g. the sqlite3_exec(...) function does, with dozens of sub-calls and operations)

You still do not seem to understand, that a function-calls total-timing (until it returns) has two parts:
1.) the call overhead (usually in the range of 1-100 nano-seconds)
2.) the time the function itself needs (to process its "implementation", aka the instructions in its function-body)

And since the above second part is (at least for sqlite3_exec) more in the range of micro-seconds,
it does not really matter for the total call-time, if you were successfully:
- reducing the __cdecl Call-Overhead from e.g. 100nano-seconds to perhaps 10nano-seconds with ASM-thunking
- when the sqlite3_exec method itself takes about 10 micro-seconds for its internal instructions in addition

To write it up in numbers... the total call-time for sqlite3_exec:
- would be about 10.1 micro-seconds (using the established cdecl-call-workarounds without any ASM-tricks)
- and it might be about 10.01 micro-seconds, if you manage the ASM-trickery successfully

Congratulations then (in case you manage the ASM-trickery).
You will then have succeeded, to call the sqlite3_exec function:
- only about 1% faster over all (compared to using the established, stable VB6-cdecl calling methods alternatively)
- whilst introducing a whole lot of potentially unstable, barely maintainable thunking-code into your App

Not a good bargain at all, if you ask me.

Olaf