windows - How to call C extern function and get return struct? -


i have extern function , struct defined in token.c:

#include "stdio.h"  typedef struct token {     int start;     int length; } t;  extern t get_token(int, int);  t get_token(int s, int l) {     printf("[c] new token: start [%d]  length [%d]\n\n", s, l);      t m_t = {};     m_t.start = s;     m_t.length = l;      return m_t; }

... can call _get_token assembly , new token. in make_token.asm have following:

section .data       ; initialized data     mtkn:       db  "call: token(%d, %d)", 10, 0     mlen        db  "length: %d", 10, 0     mstt:       db  "start: %d", 10, 0      mend:       db  10, "*** end ***", 10, 0  section .text       ; code     extern _get_token      extern _printf      global _main      _main:         ;   stash base stack pointer         push    ebp         mov     ebp,        esp          mov     eax,        5         mov     ebx,        10         push    ebx                     ; length         push    eax                     ; start         call    _get_token              ; token         mov     [tkn],      eax          add     esp,        8          ;   test token properties         push    dword [tkn]         push    mstt         call    _printf          push    dword [tkn + 4]         push    mlen         call    _printf          add     esp,        16          .end:         push    dword   mend         call    _printf         ;   restore base stack pointer         mov     esp,        ebp         pop     ebp  section .bss        ; uninitialized data     tkn:        resd        1

the output is:

[c] new token: start [5] length [10]

start: 5
length: 0

what missing both start , length? output verifies extern function in c getting called , values pushed function.

i believe problem lies in .bss section:

section .bss        ; uninitialized data     tkn:        resd        1

here, set aside single dword (one integer's worth of memory) of memory token. however, in c code, define token struct having 2 ints (start , length), or 2 dwords worth of memory. means able write part of token struct (start), , member length treated non-existent. problem can solved defining tkn as

    tkn:        resd        2

or

    tkn:        resq        1     ;; 1 qword == 2 dwords

hope helps ;)


-

Popular posts from this blog

c# - ODP.NET Oracle.ManagedDataAccess causes ORA-12537 network session end of file -

overview i want replace oracle.dataaccess orcale. managed dataaccess, opening connection latter throws ora-12537 network session end of file exception. exception message / stack trace {oracleinternal.network.networkexception (0x000030f9): ora-12537 : netzwerksession: dateiende @ oracleinternal.network.readerstream.read(orabuf ob) @ oracleinternal.ttc.orabufreader.getdatafromnetwork() @ oracleinternal.ttc.orabufreader.read(boolean bignoredata) @ oracleinternal.ttc.marshallingengine.unmarshalub1(boolean bignoredata) @ oracleinternal.ttc.ttcprotocolnegotiation.readresponse()} i trying connect oracle 11g database , not have client installed on local machine. working test application (unmanaged) using oracle.dataaccess works fine . using system; using oracle.dataaccess.client; namespace app.odp.unmanaged { internal class program { private static void main(string[] args) { //dummy connection string...
Read more

matlab - Compression and Decompression of ECG Signal using HUFFMAN ALGORITHM -

i want compress , decompress ecg signal stored text message text file , find out file size, cr,prd ratio,and qs. here code compression , decompression of ecg signal using huffman algorithm. i'm trying find out file size, compression ratio,prd ratio,qs. but error i'm getting the ecg file in text format. %clearing variables , screen enter code here clear all; close all; clc; [file1]=uigetfile('*.txt'); %fprintf('enter ecg file name :%s',file1); p=file1; t=sprintf('%s',p); b1=dlmread([file1]); len=length(b1); lead=input('enter lead number :'); %lead=str2double(lead); col2=b1(1:end,lead); e=fix(sqrt(len)); m=1; i=1:e j=1:e g2(i,j)=fix(col2(m)*1000); %amplifying 1000 m=m+1; end end g3=g2; i=1:e j=1:e ...
Read more

utf 8 - split utf-8 string into bytes in python -

i trying split utf-8 string bytes in python 3. problem is, when use bytearray, byte, encode etc functions array size of element 14 bytes, not 1 byte expected. need split text file sequence of bytes , send them byte after byte using sockets. tried this: infile = open (file, "r") str = infile.read() byte_str = bytes(str, 'utf-8') print("size of byte_str",sys.getsizeof(byte_str[0])) print gives me 14, need 1... suggestion? quoting official documentation : sys.getsizeof(object[, default]) return size of object in bytes. object can type of object. built-in objects return correct results, not have hold true third-party extensions implementation specific. only memory consumption directly attributed object accounted for, not memory consumption of objects refers to. if given, default returned if object not provide means retrieve size. otherwise typeerror raised. getsizeof() calls object’s __sizeof__ method , adds ...
Read more