/* ---------------------------------------------- *//* alloca-bt.S */ #ifdef __leading_underscore# define _(s) _##s#else# define _(s) s#endif /* ---------------------------------------------- */#if defined __i386__ .globl _(__bound_alloca)_(__bound_alloca):    pop     %edx    pop     %eax    mov     %eax, %ecx    test    %eax,%eax    jz      p6    add     $3 + 1,%eax    and     $-4,%eax #ifdef _WIN32p4:    cmp     $4096,%eax    jb      p5    test    %eax,-4096(%esp)    sub     $4096,%esp    sub     $4096,%eax    jmp p4 p5:#endif     sub     %eax,%esp    mov     %esp,%eax     push    %edx    push    %eax    push    %ecx    push    %eax    call    _(__bound_new_region)    add     $8, %esp    pop     %eax    pop     %edx p6:    push    %edx    push    %edx    ret /* ---------------------------------------------- */#elif defined __x86_64__ .globl _(__bound_alloca)_(__bound_alloca):#ifdef _WIN32    inc %rcx            # add one extra to separate regions    jmp _(alloca).globl _(__bound_alloca_nr)_(__bound_alloca_nr):    dec     %rcx    push    %rax    mov     %rcx,%rdx    mov     %rax,%rcx    sub     $32,%rsp    call    _(__bound_new_region)    add     $32,%rsp    pop     %rax    ret#else    pop     %rdx    mov     %rdi,%rax    and     %eax,%eax    jz      p3    mov     %rax,%rsi	# size, a second parm to the __bound_new_region    add     $15 + 1,%rax  # add one extra to separate regions    and     $-16,%rax     sub     %rax,%rsp    mov     %rsp,%rdi	# pointer, a first parm to the __bound_new_region    mov     %rsp,%rax     push    %rdx    push    %rax    call    _(__bound_new_region)    pop     %rax    pop     %rdx p3:    push    %rdx    ret#endif /* ---------------------------------------------- */#elif defined __arm__ .globl _(__bound_alloca)_(__bound_alloca):    mov r1, r0    add r0, r0, #1    rsb sp, r0, sp    bic sp, sp, #7    mov r0, sp    push { lr }    bl _(__bound_new_region)    pop { lr }    mov r0, sp    mov pc, lr /* ---------------------------------------------- */#elif defined __aarch64__ || defined __arm64__ .globl _(__bound_alloca)_(__bound_alloca):#ifdef __TINYC__    .int 0xaa0003e1    .int 0x91004000    .int 0x927cec00#ifdef _WIN32    .int 0xb4000160    .int 0xd2820002    .int 0xeb02001f    .int 0x540000c3    .int 0xcb2263e3    .int 0xf940007f    .int 0xcb2263ff    .int 0xcb020000    .int 0x17fffffa    .int 0xb4000040#endif    .int 0xcb2063ff    .int 0x910003e0    .int 0xa9bf7bfd    .reloc ., R_AARCH64_CALL26,  _(__bound_new_region)    .int 0x94000000    .int 0xa8c17bfd    .int 0x910003e0    .int 0xd65f03c0#else    mov x1, x0    add x0, x0, #16     // Round up to 16-byte boundary    and x0, x0, #-16    // Ensure 16-byte alignment#ifdef _WIN32    cbz x0, p100        // If size is 0, skip to return    // Windows requires page-wise allocation with stack probing    mov x2, #4096       // Page size = 4096 bytes p101:    cmp x0, x2          // Compare remaining size with page size    b.lo    p102        // If less than page, jump to remainder     // Probe first, then allocate    sub x3, sp, x2      // Calculate guard page address (sp - 4096)    ldr xzr, [x3]       // Touch guard page FIRST    sub sp, sp, x2      // THEN allocate the page     sub x0, x0, x2      // Decrement remaining size    b   p101            // Continue loop p102:    // Allocate remaining bytes (less than one page)    cbz x0, p100        // If no remaining bytes, skip    sub sp, sp, x0      // Allocate remaining space#else    // Non-Windows: simple one-time allocation    sub sp, sp, x0      // Allocate space on stack#endif p100:    mov x0, sp          // Return allocated address    stp x29, x30, [sp, #-16]!    bl _(__bound_new_region)    ldp x29, x30, [sp], #16    mov x0, sp          // Return allocated address    ret                 // Return to caller#endif /* ---------------------------------------------- */#elif defined __riscv .globl _(__bound_alloca)_(__bound_alloca):    mv     a1, a0    sub    sp, sp, a0    addi   sp, sp, -16    andi   sp, sp, -16    add    a0, sp, zero    addi   sp,sp,-16    sd     s0,0(sp)    sd     ra,8(sp)    jal    _(__bound_new_region)    ld     s0,0(sp)    ld     ra,8(sp)    addi   sp,sp,16    add    a0, sp, zero    ret /* ---------------------------------------------- */#endif