_internal_s2n_bignum_arm.h

#ifdef __APPLE__
#   define S2N_BN_SYMBOL(NAME) _##NAME
#   if defined(__AARCH64EL__) || defined(__ARMEL__)
#     define __LF %%
#   else
#     define __LF ;
#   endif
#else
#   define S2N_BN_SYMBOL(name) name
#   define __LF ;
#endif

#define S2N_BN_SYM_VISIBILITY_DIRECTIVE(name) .globl S2N_BN_SYMBOL(name)

#ifdef S2N_BN_HIDE_SYMBOLS
#   ifdef __APPLE__
#      define S2N_BN_SYM_PRIVACY_DIRECTIVE(name) .private_extern S2N_BN_SYMBOL(name)
#   else
#      define S2N_BN_SYM_PRIVACY_DIRECTIVE(name) .hidden S2N_BN_SYMBOL(name)
#   endif
#else
#   define S2N_BN_SYM_PRIVACY_DIRECTIVE(name)  /* NO-OP: S2N_BN_SYM_PRIVACY_DIRECTIVE */
#endif

#ifdef __APPLE__
#   define S2N_BN_FUNCTION_TYPE_DIRECTIVE(name) /* Not used in Mach-O */
#else
#   define S2N_BN_FUNCTION_TYPE_DIRECTIVE(name) .type name, %function
#endif

#ifdef __APPLE__
#   define S2N_BN_SIZE_DIRECTIVE(name) /* Not used in Mach-O */
#else
#   define S2N_BN_SIZE_DIRECTIVE(name) .size S2N_BN_SYMBOL(name), .-S2N_BN_SYMBOL(name)
#endif

// Enable branch target identification (BTI) support unless explicitly disabled
// with -DNO_IBT, mirroring the x86 _CET_ENDBR machinery. AARCH64_VALID_CALL_TARGET
// is emitted at each entry point unconditionally by default, since BTI 'c' is in
// the hint space and so behaves as a NOP on all pre-Armv8.5-A processors. The name
// matches AWS-LC's macro, whose definition we defer to if already present, just as
// the x86 side defers to <cet.h>. Unlike CET, BTI also needs a .note.gnu.property
// section: it has GNU_PROPERTY_AARCH64_FEATURE_1_AND semantics, so one object
// without the note silently disables BTI program-wide, hence emitting it here.

#if NO_IBT
#   if defined(AARCH64_VALID_CALL_TARGET)
#     error "The s2n-bignum build option NO_IBT was configured, but AARCH64_VALID_CALL_TARGET is defined in this compilation unit. That is weird, so failing the build."
#   endif
#   define AARCH64_VALID_CALL_TARGET
#elif !defined(AARCH64_VALID_CALL_TARGET)
#   define AARCH64_VALID_CALL_TARGET hint #34 /* BTI c */
#   ifndef __APPLE__
        .pushsection .note.gnu.property, "a"
        .balign 8
        .long 4                   /* n_namesz: sizeof "GNU\0" */
        .long 0x10                /* n_descsz: 16 bytes of property data */
        .long 0x5                 /* n_type: NT_GNU_PROPERTY_TYPE_0 */
        .asciz "GNU"
        .long 0xc0000000          /* pr_type: GNU_PROPERTY_AARCH64_FEATURE_1_AND */
        .long 4                   /* pr_datasz: 4 bytes */
        .long 1                   /* pr_data: GNU_PROPERTY_AARCH64_FEATURE_1_BTI */
        .long 0                   /* pad to 8-byte alignment */
        .popsection
#   endif
#endif

// Variants of instructions including CFI (call frame information) annotations

#define CFI_START .cfi_startproc
#define CFI_RET ret __LF .cfi_endproc

#define CFI_BL(target) bl target

#define CFI_PUSH2(lo,hi) stp     lo, hi, [sp, #-16]! __LF .cfi_adjust_cfa_offset 16 __LF .cfi_rel_offset lo, 0 __LF .cfi_rel_offset hi, 8
#define CFI_PUSH1Z(reg) stp     reg, xzr, [sp, #-16]! __LF .cfi_adjust_cfa_offset 16 __LF .cfi_rel_offset reg, 0

#define CFI_POP2(lo,hi) ldp     lo, hi, [sp], #16 __LF .cfi_adjust_cfa_offset -16 __LF .cfi_restore lo __LF .cfi_restore hi
#define CFI_POP1Z(reg) ldp     reg, xzr, [sp], #16 __LF .cfi_adjust_cfa_offset -16 __LF .cfi_restore reg

#define CFI_STACKSAVE2(lo,hi,offset) stp     lo, hi, [sp, #(offset)] __LF .cfi_rel_offset lo, offset __LF .cfi_rel_offset hi, offset+8

// This is an alternative to CFI_STACKSAVE2 to work around delocator problems
// in the AWS-LC FIPS build, avoiding certain composite expressions. It is
// expected that offset8 = offset+8 as in an invocation of CFI_STACKSAVE2.
// Likewise the (offset+0) oddities in the following macros are driven by
// delocator problems.

#define CFI_STACKSAVE2X(lo,hi,offset,offset8) stp     lo, hi, [sp, #(offset+0)] __LF .cfi_rel_offset lo, offset __LF .cfi_rel_offset hi, offset8

#define CFI_STACKSAVE1Z(reg,offset) stp     reg, xzr, [sp, #(offset+0)] __LF .cfi_rel_offset reg, offset

#define CFI_STACKLOAD2(lo,hi,offset) ldp     lo, hi, [sp, #(offset+0)] __LF .cfi_restore lo __LF .cfi_restore hi
#define CFI_STACKLOAD1Z(reg,offset) ldp     reg, xzr, [sp, #(offset+0)] __LF .cfi_restore reg

// It would be better to use -(offset) not -offset, but again there seem
// to be delocator issues. We adopt a discipline of not using dangerous
// composite expressions in this macro, e.g. parenthesizing the argument
// or just using numeric constants or products where the association is
// not a problem.

#define CFI_INC_SP(offset) add     sp, sp, #(offset+0) __LF .cfi_adjust_cfa_offset -offset
#define CFI_DEC_SP(offset) sub     sp, sp, #(offset+0) __LF .cfi_adjust_cfa_offset offset