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Why can't I use more than two registers in inline asm?


By : GoldanLevitt
Date : September 16 2020, 08:00 PM
I think the issue was by ths following , For that specific error, the ); should not be where you have it (where I've indicated below).
code :
__asm(
"add %eex, %edx\n"
"add %eax, %ecx\n"
"mov 1 ,%0\n"
:"=r"(side)
:"a"(map.y));    <---
:"e"(sdist.y)
:"d"(delta.y)
:"c"(step.y)
);


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Inline assembly in C: Dynamic registers


By : user1482867
Date : March 29 2020, 07:55 AM
this will help I'm trying to inline some assembly code in my C code: , Use an enum and switch in the C-code:
code :
typedef enum
{
  R_AL,
  R_AH,
  R_AX,
  R_EAX,
...
} REGS;
...
REGS nReg;
...
switch (nReg)
{
    case R_AL: __asm { mov al,val } break;    
    case R_AH: __asm { mov ah,val } break;    
    case R_AX: __asm { mov ax,val } break;
    ...
}

Using registers and inline assembly (ARM)


By : user3005549
Date : March 29 2020, 07:55 AM
Any of those help The implementation translated to 3 instructions very likely because you didn't enable any optimisations.
However, from a quick test, it looks like you'll have to write inline assembly anyway because when I compile the following using -O3 -fomit-frame-pointer
code :
void test(void) {
        register unsigned int cycles asm("r6");
        while(1) cycles++;
}
00000000 <test>:
   0:   eafffffe    b   0 <test>
<                    your process                     >
|<---------------your alarm duration----------------->|
<your process> | <other processes ...> | <your process>
|<---------------your alarm duration----------------->|

Can't force the use of 64-bit registers in GCC inline assembly


By : Saeid Hoseini
Date : March 29 2020, 07:55 AM
hope this fix your issue I'm trying to make some things with GCC Inline Assembly, in this case, make a Syscall, but I want to force use of 64bit registers (rax, rdi, rsi, ...) instead of 32bit ones (eax, edi, ...), but I tried a lot of ways, and nothing. , This actually sets the RAX register to 60:
code :
mov eax, 60
static inline __attribute__ ((always_inline)) void
syscall(uint64_t arg1, uint64_t arg2)
{
   __asm__("mov rax, %0; syscall" : : "i" (arg1), "D" (arg2) : "rax");
}

Inline Assembler: What scratch registers can be used?


By : Ternsip
Date : March 29 2020, 07:55 AM
To fix this issue Inline assembly is, by definition, compiler-specific.
Most compilers that support inline assembly have a syntax that allows you to indicate which registers are modified by the assembly. The compiler can then save and restore those registers as needed.

Why Motorola 68k's 32-bit general-purpose registers are divided into data registers and address registers?


By : Muhammad Arshan
Date : March 29 2020, 07:55 AM
I hope this helps . The short answer is, this separation comes from the architecture limitations and design decisions made at the time.
The long answer:
code :
move.l $10(pc), -$20(a0,d0.l)
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