symbian-qemu-0.9.1-12/libpng-1.2.32/pnggccrd.c
author johnathan.white@2718R8BGH51.accenture.com
Mon, 08 Mar 2010 18:45:03 +0000
changeset 46 b6935a90ca64
parent 1 2fb8b9db1c86
permissions -rw-r--r--
Modify framebuffer and NGA framebuffer to read screen size from board model dtb file. Optimise memory usuage of frame buffer Add example minigui application with hooks to profiler (which writes results to S:\). Modified NGA framebuffer to run its own dfc queue at high priority

/* pnggccrd.c was removed from libpng-1.2.20. */

/* This code snippet is for use by configure's compilation test. */

#if (!defined _MSC_VER) && \
    defined(PNG_ASSEMBLER_CODE_SUPPORTED) && \
    defined(PNG_MMX_CODE_SUPPORTED)

int PNGAPI png_dummy_mmx_support(void);

static int _mmx_supported = 2; // 0: no MMX; 1: MMX supported; 2: not tested

int PNGAPI
png_dummy_mmx_support(void) __attribute__((noinline));

int PNGAPI
png_dummy_mmx_support(void)
{
   int result;
#if defined(PNG_MMX_CODE_SUPPORTED)  // superfluous, but what the heck
    __asm__ __volatile__ (
#if defined(__x86_64__)
        "pushq %%rbx          \n\t"  // rbx gets clobbered by CPUID instruction
        "pushq %%rcx          \n\t"  // so does rcx...
        "pushq %%rdx          \n\t"  // ...and rdx (but rcx & rdx safe on Linux)
        "pushfq               \n\t"  // save Eflag to stack
        "popq %%rax           \n\t"  // get Eflag from stack into rax
        "movq %%rax, %%rcx    \n\t"  // make another copy of Eflag in rcx
        "xorl $0x200000, %%eax \n\t" // toggle ID bit in Eflag (i.e., bit 21)
        "pushq %%rax          \n\t"  // save modified Eflag back to stack
        "popfq                \n\t"  // restore modified value to Eflag reg
        "pushfq               \n\t"  // save Eflag to stack
        "popq %%rax           \n\t"  // get Eflag from stack
        "pushq %%rcx          \n\t"  // save original Eflag to stack
        "popfq                \n\t"  // restore original Eflag
#else
        "pushl %%ebx          \n\t"  // ebx gets clobbered by CPUID instruction
        "pushl %%ecx          \n\t"  // so does ecx...
        "pushl %%edx          \n\t"  // ...and edx (but ecx & edx safe on Linux)
        "pushfl               \n\t"  // save Eflag to stack
        "popl %%eax           \n\t"  // get Eflag from stack into eax
        "movl %%eax, %%ecx    \n\t"  // make another copy of Eflag in ecx
        "xorl $0x200000, %%eax \n\t" // toggle ID bit in Eflag (i.e., bit 21)
        "pushl %%eax          \n\t"  // save modified Eflag back to stack
        "popfl                \n\t"  // restore modified value to Eflag reg
        "pushfl               \n\t"  // save Eflag to stack
        "popl %%eax           \n\t"  // get Eflag from stack
        "pushl %%ecx          \n\t"  // save original Eflag to stack
        "popfl                \n\t"  // restore original Eflag
#endif
        "xorl %%ecx, %%eax    \n\t"  // compare new Eflag with original Eflag
        "jz 0f                \n\t"  // if same, CPUID instr. is not supported

        "xorl %%eax, %%eax    \n\t"  // set eax to zero
//      ".byte  0x0f, 0xa2    \n\t"  // CPUID instruction (two-byte opcode)
        "cpuid                \n\t"  // get the CPU identification info
        "cmpl $1, %%eax       \n\t"  // make sure eax return non-zero value
        "jl 0f                \n\t"  // if eax is zero, MMX is not supported

        "xorl %%eax, %%eax    \n\t"  // set eax to zero and...
        "incl %%eax           \n\t"  // ...increment eax to 1.  This pair is
                                     // faster than the instruction "mov eax, 1"
        "cpuid                \n\t"  // get the CPU identification info again
        "andl $0x800000, %%edx \n\t" // mask out all bits but MMX bit (23)
        "cmpl $0, %%edx       \n\t"  // 0 = MMX not supported
        "jz 0f                \n\t"  // non-zero = yes, MMX IS supported

        "movl $1, %%eax       \n\t"  // set return value to 1
        "jmp  1f              \n\t"  // DONE:  have MMX support

    "0:                       \n\t"  // .NOT_SUPPORTED: target label for jump instructions
        "movl $0, %%eax       \n\t"  // set return value to 0
    "1:                       \n\t"  // .RETURN: target label for jump instructions
#if defined(__x86_64__)
        "popq %%rdx           \n\t"  // restore rdx
        "popq %%rcx           \n\t"  // restore rcx
        "popq %%rbx           \n\t"  // restore rbx
#else
        "popl %%edx           \n\t"  // restore edx
        "popl %%ecx           \n\t"  // restore ecx
        "popl %%ebx           \n\t"  // restore ebx
#endif

//      "ret                  \n\t"  // DONE:  no MMX support
                                     // (fall through to standard C "ret")

        : "=a" (result)              // output list

        :                            // any variables used on input (none)

                                     // no clobber list
//      , "%ebx", "%ecx", "%edx"     // GRR:  we handle these manually
//      , "memory"   // if write to a variable gcc thought was in a reg
//      , "cc"       // "condition codes" (flag bits)
    );
    _mmx_supported = result;
#else
    _mmx_supported = 0;
#endif /* PNG_MMX_CODE_SUPPORTED */

    return _mmx_supported;
}
#endif