tinycc/lib/alloca86_64.S

/* ---------------------------------------------- */
/* alloca86_64.S */

.globl alloca

alloca:
    pop     %rdx
#ifdef TCC_TARGET_PE
    mov     %rcx,%rax
#else
    mov     %rdi,%rax
#endif
    add     $15,%rax
    and     $-16,%rax
    jz      p3

#ifdef TCC_TARGET_PE
p1:
    cmp     $4096,%rax
    jbe     p2
    test    %rax,-4096(%rsp)
    sub     $4096,%rsp
    sub     $4096,%rax
    jmp p1
p2:
#endif

    sub     %rax,%rsp
    mov     %rsp,%rax
p3:
    push    %rdx
    ret

/* ---------------------------------------------- */
x86-64: Add alloca. 2009-06-08 22:23:08 +04:00			`/* ---------------------------------------------- */`
			`/* alloca86_64.S */`

			`.globl alloca`

			`alloca:`
			`pop %rdx`
x86-64: chkstk, alloca 2009-07-19 00:06:54 +04:00			`#ifdef TCC_TARGET_PE`
			`mov %rcx,%rax`
			`#else`
x86-64: Add alloca. 2009-06-08 22:23:08 +04:00			`mov %rdi,%rax`
x86-64: chkstk, alloca 2009-07-19 00:06:54 +04:00			`#endif`
x86-64: Align return value of alloca by 16. 2009-06-11 03:33:41 +04:00			`add $15,%rax`
			`and $-16,%rax`
x86-64: Add alloca. 2009-06-08 22:23:08 +04:00			`jz p3`

			`#ifdef TCC_TARGET_PE`
			`p1:`
			`cmp $4096,%rax`
Fix mistake. Change jb by jbe. tiny c round (INT_MAX = 0x7FFFFFFF) to a DWORD boundary and it becomes 0x80000000. Jle treats as -214783648, but Jbe treats as 214783648. Thanks to Jason Hood for explain me this. 2014-07-11 04:41:51 +04:00			`jbe p2`
Fix problem using alloca function, executable crashed even with a exception handler function, when try to allocate INT_MAX. Patch provided by Jason Hood in private e-mail, when I ask to him for help. He say: Feel free to pass it on to the mailing list. 2014-07-10 08:37:20 +04:00			`test %rax,-4096(%rsp)`
x86-64: Add alloca. 2009-06-08 22:23:08 +04:00			`sub $4096,%rsp`
			`sub $4096,%rax`
			`jmp p1`
			`p2:`
			`#endif`

			`sub %rax,%rsp`
			`mov %rsp,%rax`
			`p3:`
			`push %rdx`
			`ret`

			`/* ---------------------------------------------- */`