Inline functions in C, gcc optimization and floating point arithmetic issues

Question

For several days I really have become a fan of Alchemy. But after intensive testing I have found several issues which I'd like to solve but I can't without any help.
So...I'm porting an old game console emulator written by me in ANSI C. The code is working on both gcc and VisualStudio without any modification or crosscompile macros. The only platform code is the audio and video output which is out of scope, because I have ported audio and video witin AS3.
Here are the issues:
1. Inline functions - Having only a single inline function makes the code working incorrectly (although not crashing) even if any optimization is enabled or not (-O0 or O3). My current workarround is converting the inline functions to macros which achieves the same effect. Any ideas why inline functions break the code?
2. Compiler optimizations - well, my project consists of many C files one of which is called flash.c and it contains the main and exported functions. I build the project as follows:
gcc -c flash.c -O0 -o flash.o     //Please note the -O0 option!!!
gcc -c file1.c -O3 -o file1.o
gcc -c file2.c -O3 -o file2.o
... and so on
gcc *.o -swc -O0 -o emu.swc   //Please note the -O0 option again!!!
mxmlc.exe -library-path+=emu.swc --target-player=10.0.0 Emu.as
or file in $( ls *.o ) //Removes the obj files
    do
        rm $file
    done
If I define any option different from -O0 in gcc -c flash.c -O0 -o flash.o the program stops working correctly exactly as in the inline funtions code (but still does not crash or prints any errors in debug). flash has 4 static functions to be exported to AS3 and the main function. Do you know why?
If I define any option different from -O0 in gcc *.o -swc -O0 -o emu.swc  the program stops working correctly exactly as above, but if I specify -O1, -O2 or O3 the SWC file gets smaller up to 2x for O3. Why? Is there a method to optimize all the obj files except flash.o because I suspect a similar issue as when compilling it?
3. Flating point issues - this is the worst one. My code is mainly based on integer arithmetic but on 1-2 places it requires flating point arithmetic. One of them is the conversion of 16-bit 44.1 Khz sound buffer to a float buffer with same sample rate but with samples in the range from -1.0 to 1.0.
My code:
void audio_prepare_as()
    uint32 i;
    for(i=0;i<audioSamples;i+=2)
        audiobuffer[i] = (float)snd.buffer[i]/32768;
        audiobuffer[i+1] = (float)snd.buffer[i+1]/32768;
My audio playback is working perfectly. But not if using the above conversion and I have inspected the float numbers - all incorrect and invalid. I tried other code with simple floats - same story. As if alchemy refuses to work with floats. What is wrong? I have another lace whre I must resize the framebuffer and there I have a float involved - same crap. Please help me?
Found the floating point problem: audiobuffer is written to a ByteArray and then used in AS. But C floats are obviously not the same as those in AS3. Now the floating point is resolved.
The optimization issues remain! I really need to speed up my code.
Thank you in advice!

Answer 1

Dear Bernd,
I am still unable to run the optimizations and turn on the inline functions. None of the inline functions contain any stdli function just pure asignments, reads, simple arithmetic and bitwise operations.
In fact, the file containing the main function and those functions for export in AS3 did have memset and memcpy. I tried your suggestion and put the code above the functions calling memset and memcpy. It did not work soe I put the code in a header which is included topmost in each C file. The only system header I use is malloc.h and it is included topmost. In other C file I use pow, sin and log10 from math.h but I removed it and made the same thing:
//shared.h
#ifndef _SHARED_H_
#define _SHARED_H_
#include <malloc.h>
static void * custom_memmove( void * destination, const void * source, unsigned int num ) {
  void *result; 
  __asm__("%0 memmove(%1, %2, %3)\n" : "=r"(result) : "r"(destination), "r"(source), "r"(num)); 
  return result; 
static void * custom_memcpy ( void * destination, const void * source, unsigned int num ) { 
  void *result; 
  __asm__("%0 memcpy(%1, %2, %3)\n" : "=r"(result) : "r"(destination), "r"(source), "r"(num)); 
  return result; 
static void * custom_memset ( void * ptr, int value, unsigned int num ) { 
  void *result; 
  __asm__("%0 memset(%1, %2, %3)\n" : "=r"(result) : "r"(ptr), "r"(value), "r"(num)); 
  return result; 
static float custom_pow(float x, int y) {
    float result;
  __asm__("%0 pow(%1, %2)\n" : "=r"(result) : "r"(x), "r"(y));
  return result;
static double custom_sin(double x) {
    double result;
  __asm__("%0 sin(%1)\n" : "=r"(result) : "r"(x));
  return result;
static double custom_log10(double x) {
    double result;
  __asm__("%0 log10(%1)\n" : "=r"(result) : "r"(x));
  return result;
#define memmove custom_memmove
#define memcpy custom_memcpy
#define memset custom_memset
#define pow custom_pow
#define sin custom_sin
#define log10 custom_log10 
#include "types.h"
#include "macros.h"
#include "m68k.h"
#include "z80.h"
#include "genesis.h"
#include "vdp.h"
#include "render.h"
#include "mem68k.h"
#include "memz80.h"
#include "membnk.h"
#include "memvdp.h"
#include "system.h"
#include "loadrom.h"
#include "input.h"
#include "io.h"
#include "sound.h"
#include "fm.h"
#include "sn76496.h" 
#endif /* _SHARED_H_ */ 
It still behave the same way as if nothing was changed (works incorrectly - displays jerk which does not move, whereby the image is supposed to move)
As I am porting an emulator (Sega Mega Drive) I use manu arrays of function pointers for implementing the opcodes of the CPU's. Could this be an issue?
I did a workaround for the floating point problem but processing is very slow so I hear only bzzt bzzt but this is for now out of scope. The emulator compiled with gcc runs at 300 fps on a 1.3 GHz machine, whereby my non optimized AVM2 code compiled by alchemy produces 14 fps. The pure rendering is super fast and the problem lies in the computational power of AVM. The frame buffer and the enulation are generated in the C code and only the pixels are copied to AS3, where they are plotted in a BitmapData. On 2.0 GHz Dual core I achieved only 21 fps. Goal is 60 fps to have smooth audio and video. But this is offtopic. After all everything works (slow) without optimization, and I would somehow turn it on. Suggestions?
Here is the file with the main function:
#include "shared.h"
#include "AS3.h"
#define FRAMEBUFFER_LENGTH    (320*240*4)
static uint8* framebuffer;
static uint32  audioSamples;
AS3_Val sega_rom(void* self, AS3_Val args)
    int size, offset, i;
    uint8 hardware;
    uint8 country;
    uint8 header[0x200];
    uint8 *ptr;
    AS3_Val length;
    AS3_Val ba;
    AS3_ArrayValue(args, "AS3ValType", &ba);
    country = 0;
    offset = 0;
    length = AS3_GetS(ba, "length");
    size = AS3_IntValue(length);
    ptr = (uint8*)malloc(size);
    AS3_SetS(ba, "position", AS3_Int(0));
    AS3_ByteArray_readBytes(ptr, ba, size);
    //FILE* f = fopen("boris_dump.bin", "wb");
    //fwrite(ptr, size, 1, f);
    //fclose(f);
    if((size / 512) & 1)
        size -= 512;
        offset += 512;
        memcpy(header, ptr, 512);
        for(i = 0; i < (size / 0x4000); i += 1)
            deinterleave_block(ptr + offset + (i * 0x4000));
    memset(cart_rom, 0, 0x400000);
    if(size > 0x400000) size = 0x400000;
    memcpy(cart_rom, ptr + offset, size);
    /* Free allocated file data */
    free(ptr);
    hardware = 0;
    for (i = 0x1f0; i < 0x1ff; i++)
        switch (cart_rom[i]) {
     case 'U':
         hardware |= 4;
         break;
     case 'J':
         hardware |= 1;
         break;
     case 'E':
         hardware |= 8;
         break;
    if (cart_rom[0x1f0] >= '1' && cart_rom[0x1f0] <= '9') {
        hardware = cart_rom[0x1f0] - '0';
    } else if (cart_rom[0x1f0] >= 'A' && cart_rom[0x1f0] <= 'F') {
        hardware = cart_rom[0x1f0] - 'A' + 10;
    if (country) hardware=country; //simple autodetect override
    //From PicoDrive
    if (hardware&8)        
        hw=0xc0; vdp_pal=1;
    } // Europe
    else if (hardware&4)    
        hw=0x80; vdp_pal=0;
    } // USA
    else if (hardware&2)    
        hw=0x40; vdp_pal=1;
    } // Japan PAL
    else if (hardware&1)      
        hw=0x00; vdp_pal=0;
    } // Japan NTSC
    else
        hw=0x80; // USA
    if (vdp_pal) {
        vdp_rate = 50;
        lines_per_frame = 312;
    } else {
        vdp_rate = 60;
        lines_per_frame = 262;
    /*SRAM*/   
    if(cart_rom[0x1b1] == 'A' && cart_rom[0x1b0] == 'R')
        save_start = cart_rom[0x1b4] << 24 | cart_rom[0x1b5] << 16 |
            cart_rom[0x1b6] << 8  | cart_rom[0x1b7] << 0;
        save_len = cart_rom[0x1b8] << 24 | cart_rom[0x1b9] << 16 |
            cart_rom[0x1ba] << 8  | cart_rom[0x1bb] << 0;
        // Make sure start is even, end is odd, for alignment
        // A ROM that I came across had the start and end bytes of
        // the save ram the same and wouldn't work.  Fix this as seen
        // fit, I know it could probably use some work. [PKH]
        if(save_start != save_len)
            if(save_start & 1) --save_start;
            if(!(save_len & 1)) ++save_len;
            save_len -= (save_start - 1);
            saveram = (unsigned char*)malloc(save_len);
            // If save RAM does not overlap main ROM, set it active by default since
            // a few games can't manage to properly switch it on/off.
            if(save_start >= (unsigned)size)
                save_active = 1;
        else
            save_start = save_len = 0;
            saveram = NULL;
    else
        save_start = save_len = 0;
        saveram = NULL;
    return AS3_Int(0);
AS3_Val sega_init(void* self, AS3_Val args)
    system_init();
    audioSamples = (44100 / vdp_rate)*2;
    framebuffer = (uint8*)malloc(FRAMEBUFFER_LENGTH);
    return AS3_Int(vdp_rate);
AS3_Val sega_reset(void* self, AS3_Val args)
    system_reset();
    return AS3_Int(0);
AS3_Val sega_frame(void* self, AS3_Val args)
    uint32 width;
    uint32 height;
    uint32 x, y;
    uint32 di, si, r;
    uint16 p;
    AS3_Val fb_ba;
    AS3_ArrayValue(args, "AS3ValType", &fb_ba);
    system_frame(0);
    AS3_SetS(fb_ba, "position", AS3_Int(0));
    width = (reg[12] & 1) ? 320 : 256;
    height = (reg[1] & 8) ? 240 : 224;
    for(y=0;y<240;y++)
        for(x=0;x<320;x++)
            di = 1280*y + x<<2;
            si = (y << 10) + ((x + bitmap.viewport.x) << 1);
            p = *((uint16*)(bitmap.data + si));
            framebuffer[di + 3] = (uint8)((p & 0x1f) << 3);
            framebuffer[di + 2] = (uint8)(((p >> 5) & 0x1f) << 3);
            framebuffer[di + 1] = (uint8)(((p >> 10) & 0x1f) << 3);
    AS3_ByteArray_writeBytes(fb_ba, framebuffer, FRAMEBUFFER_LENGTH);
    AS3_SetS(fb_ba, "position", AS3_Int(0));
    r = (width << 16) | height;
    return AS3_Int(r);
AS3_Val sega_audio(void* self, AS3_Val args)
    AS3_Val ab_ba;
    AS3_ArrayValue(args, "AS3ValType", &ab_ba);
    AS3_SetS(ab_ba, "position", AS3_Int(0));
    AS3_ByteArray_writeBytes(ab_ba, snd.buffer, audioSamples*sizeof(int16));
    AS3_SetS(ab_ba, "position", AS3_Int(0));
    return AS3_Int(0);
int main()
    AS3_Val romMethod = AS3_Function(NULL, sega_rom);
    AS3_Val initMethod = AS3_Function(NULL, sega_init);
    AS3_Val resetMethod = AS3_Function(NULL, sega_reset);
    AS3_Val frameMethod = AS3_Function(NULL, sega_frame);
    AS3_Val audioMethod = AS3_Function(NULL, sega_audio);
    // construct an object that holds references to the functions
    AS3_Val result = AS3_Object("sega_rom: AS3ValType, sega_init: AS3ValType, sega_reset: AS3ValType, sega_frame: AS3ValType, sega_audio: AS3ValType",
        romMethod, initMethod, resetMethod, frameMethod, audioMethod);
    // Release
    AS3_Release(romMethod);
    AS3_Release(initMethod);
    AS3_Release(resetMethod);
    AS3_Release(frameMethod);
    AS3_Release(audioMethod);
    // notify that we initialized -- THIS DOES NOT RETURN!
    AS3_LibInit(result);
    // should never get here!
    return 0;