blob: f71e89d41bfdde089fd58ec6ac79a7291e8c28c3 [file] [log] [blame]
/* Copyright 2015, Kenneth MacKay. Licensed under the BSD 2-clause license. */
#ifndef _UECC_ASM_ARM_H_
#define _UECC_ASM_ARM_H_
#include "asm_arm_mult_square.inc"
#if (uECC_SUPPORTS_secp256r1 || uECC_SUPPORTS_secp256k1)
#define uECC_MIN_WORDS 8
#endif
#if uECC_SUPPORTS_secp224r1
#undef uECC_MIN_WORDS
#define uECC_MIN_WORDS 7
#endif
#if uECC_SUPPORTS_secp192r1
#undef uECC_MIN_WORDS
#define uECC_MIN_WORDS 6
#endif
#if uECC_SUPPORTS_secp160r1
#undef uECC_MIN_WORDS
#define uECC_MIN_WORDS 5
#endif
#if (uECC_PLATFORM == uECC_arm_thumb)
#define REG_RW "+l"
#define REG_WRITE "=l"
#else
#define REG_RW "+r"
#define REG_WRITE "=r"
#endif
#if (uECC_PLATFORM == uECC_arm_thumb2)
#define RESUME_SYNTAX
#else
#define RESUME_SYNTAX ".syntax divided \n\t"
#endif
#if (uECC_OPTIMIZATION_LEVEL >= 2)
uECC_VLI_API uECC_word_t uECC_vli_add(uECC_word_t *result,
const uECC_word_t *left,
const uECC_word_t *right,
wordcount_t num_words) {
#if (uECC_PLATFORM == uECC_arm_thumb) || (uECC_PLATFORM == uECC_arm_thumb2)
uint32_t jump = ((uECC_MAX_WORDS - num_words) * 4 + 5) * 2 + 1;
#else /* ARM */
uint32_t jump = ((uECC_MAX_WORDS - num_words) * 4 + 5) * 4;
#endif
uint32_t carry;
uint32_t left_word;
uint32_t right_word;
__asm__ volatile (
".syntax unified \n\t"
"movs %[carry], #0 \n\t"
"mov %[left], pc \n\t"
"adds %[jump], %[left] \n\t"
"ldmia %[lptr]!, {%[left]} \n\t"
"ldmia %[rptr]!, {%[right]} \n\t"
"adds %[left], %[right] \n\t"
"stmia %[dptr]!, {%[left]} \n\t"
"bx %[jump] \n\t"
"ldmia %[lptr]!, {%[left]} \n\t"
"ldmia %[rptr]!, {%[right]} \n\t"
"adcs %[left], %[right] \n\t"
"stmia %[dptr]!, {%[left]} \n\t"
"ldmia %[lptr]!, {%[left]} \n\t"
"ldmia %[rptr]!, {%[right]} \n\t"
"adcs %[left], %[right] \n\t"
"stmia %[dptr]!, {%[left]} \n\t"
"ldmia %[lptr]!, {%[left]} \n\t"
"ldmia %[rptr]!, {%[right]} \n\t"
"adcs %[left], %[right] \n\t"
"stmia %[dptr]!, {%[left]} \n\t"
"ldmia %[lptr]!, {%[left]} \n\t"
"ldmia %[rptr]!, {%[right]} \n\t"
"adcs %[left], %[right] \n\t"
"stmia %[dptr]!, {%[left]} \n\t"
#if (uECC_MAX_WORDS >= 6)
"ldmia %[lptr]!, {%[left]} \n\t"
"ldmia %[rptr]!, {%[right]} \n\t"
"adcs %[left], %[right] \n\t"
"stmia %[dptr]!, {%[left]} \n\t"
#endif
#if (uECC_MAX_WORDS >= 7)
"ldmia %[lptr]!, {%[left]} \n\t"
"ldmia %[rptr]!, {%[right]} \n\t"
"adcs %[left], %[right] \n\t"
"stmia %[dptr]!, {%[left]} \n\t"
#endif
#if (uECC_MAX_WORDS >= 8)
"ldmia %[lptr]!, {%[left]} \n\t"
"ldmia %[rptr]!, {%[right]} \n\t"
"adcs %[left], %[right] \n\t"
"stmia %[dptr]!, {%[left]} \n\t"
#endif
"adcs %[carry], %[carry] \n\t"
RESUME_SYNTAX
: [dptr] REG_RW (result), [lptr] REG_RW (left), [rptr] REG_RW (right),
[carry] REG_WRITE (carry), [left] REG_WRITE (left_word), [right] REG_WRITE (right_word),
[jump] REG_RW (jump)
:
: "cc", "memory"
);
return carry;
}
#define asm_add 1
uECC_VLI_API uECC_word_t uECC_vli_sub(uECC_word_t *result,
const uECC_word_t *left,
const uECC_word_t *right,
wordcount_t num_words) {
#if (uECC_PLATFORM == uECC_arm_thumb) || (uECC_PLATFORM == uECC_arm_thumb2)
uint32_t jump = ((uECC_MAX_WORDS - num_words) * 4 + 5) * 2 + 1;
#else /* ARM */
uint32_t jump = ((uECC_MAX_WORDS - num_words) * 4 + 5) * 4;
#endif
uint32_t carry;
uint32_t left_word;
uint32_t right_word;
__asm__ volatile (
".syntax unified \n\t"
"movs %[carry], #0 \n\t"
"mov %[left], pc \n\t"
"adds %[jump], %[left] \n\t"
"ldmia %[lptr]!, {%[left]} \n\t"
"ldmia %[rptr]!, {%[right]} \n\t"
"subs %[left], %[right] \n\t"
"stmia %[dptr]!, {%[left]} \n\t"
"bx %[jump] \n\t"
"ldmia %[lptr]!, {%[left]} \n\t"
"ldmia %[rptr]!, {%[right]} \n\t"
"sbcs %[left], %[right] \n\t"
"stmia %[dptr]!, {%[left]} \n\t"
"ldmia %[lptr]!, {%[left]} \n\t"
"ldmia %[rptr]!, {%[right]} \n\t"
"sbcs %[left], %[right] \n\t"
"stmia %[dptr]!, {%[left]} \n\t"
"ldmia %[lptr]!, {%[left]} \n\t"
"ldmia %[rptr]!, {%[right]} \n\t"
"sbcs %[left], %[right] \n\t"
"stmia %[dptr]!, {%[left]} \n\t"
"ldmia %[lptr]!, {%[left]} \n\t"
"ldmia %[rptr]!, {%[right]} \n\t"
"sbcs %[left], %[right] \n\t"
"stmia %[dptr]!, {%[left]} \n\t"
#if (uECC_MAX_WORDS >= 6)
"ldmia %[lptr]!, {%[left]} \n\t"
"ldmia %[rptr]!, {%[right]} \n\t"
"sbcs %[left], %[right] \n\t"
"stmia %[dptr]!, {%[left]} \n\t"
#endif
#if (uECC_MAX_WORDS >= 7)
"ldmia %[lptr]!, {%[left]} \n\t"
"ldmia %[rptr]!, {%[right]} \n\t"
"sbcs %[left], %[right] \n\t"
"stmia %[dptr]!, {%[left]} \n\t"
#endif
#if (uECC_MAX_WORDS >= 8)
"ldmia %[lptr]!, {%[left]} \n\t"
"ldmia %[rptr]!, {%[right]} \n\t"
"sbcs %[left], %[right] \n\t"
"stmia %[dptr]!, {%[left]} \n\t"
#endif
"adcs %[carry], %[carry] \n\t"
RESUME_SYNTAX
: [dptr] REG_RW (result), [lptr] REG_RW (left), [rptr] REG_RW (right),
[carry] REG_WRITE (carry), [left] REG_WRITE (left_word), [right] REG_WRITE (right_word),
[jump] REG_RW (jump)
:
: "cc", "memory"
);
return !carry; /* Note that on ARM, carry flag set means "no borrow" when subtracting
(for some reason...) */
}
#define asm_sub 1
#endif /* (uECC_OPTIMIZATION_LEVEL >= 2) */
#if (uECC_OPTIMIZATION_LEVEL >= 3)
#define FAST_MULT_ASM_5_TO_6 \
"cmp r3, #5 \n\t" \
"beq 1f \n\t" \
\
/* r4 = left high, r5 = right high */ \
"ldr r4, [r1] \n\t" \
"ldr r5, [r2] \n\t" \
\
"sub r0, #20 \n\t" \
"sub r1, #20 \n\t" \
"sub r2, #20 \n\t" \
\
"ldr r6, [r0] \n\t" \
"ldr r7, [r1], #4 \n\t" \
"ldr r8, [r2], #4 \n\t" \
"mov r14, #0 \n\t" \
"umull r9, r10, r4, r8 \n\t" \
"umull r11, r12, r5, r7 \n\t" \
"adds r9, r6 \n\t" \
"adc r10, #0 \n\t" \
"adds r9, r11 \n\t" \
"adcs r10, r12 \n\t" \
"adc r14, #0 \n\t" \
"str r9, [r0], #4 \n\t" \
\
"ldr r6, [r0] \n\t" \
"adds r10, r6 \n\t" \
"adcs r14, #0 \n\t" \
"ldr r7, [r1], #4 \n\t" \
"ldr r8, [r2], #4 \n\t" \
"mov r9, #0 \n\t" \
"umull r11, r12, r4, r8 \n\t" \
"adds r10, r11 \n\t" \
"adcs r14, r12 \n\t" \
"adc r9, #0 \n\t" \
"umull r11, r12, r5, r7 \n\t" \
"adds r10, r11 \n\t" \
"adcs r14, r12 \n\t" \
"adc r9, #0 \n\t" \
"str r10, [r0], #4 \n\t" \
\
"ldr r6, [r0] \n\t" \
"adds r14, r6 \n\t" \
"adcs r9, #0 \n\t" \
"ldr r7, [r1], #4 \n\t" \
"ldr r8, [r2], #4 \n\t" \
"mov r10, #0 \n\t" \
"umull r11, r12, r4, r8 \n\t" \
"adds r14, r11 \n\t" \
"adcs r9, r12 \n\t" \
"adc r10, #0 \n\t" \
"umull r11, r12, r5, r7 \n\t" \
"adds r14, r11 \n\t" \
"adcs r9, r12 \n\t" \
"adc r10, #0 \n\t" \
"str r14, [r0], #4 \n\t" \
\
"ldr r6, [r0] \n\t" \
"adds r9, r6 \n\t" \
"adcs r10, #0 \n\t" \
"ldr r7, [r1], #4 \n\t" \
"ldr r8, [r2], #4 \n\t" \
"mov r14, #0 \n\t" \
"umull r11, r12, r4, r8 \n\t" \
"adds r9, r11 \n\t" \
"adcs r10, r12 \n\t" \
"adc r14, #0 \n\t" \
"umull r11, r12, r5, r7 \n\t" \
"adds r9, r11 \n\t" \
"adcs r10, r12 \n\t" \
"adc r14, #0 \n\t" \
"str r9, [r0], #4 \n\t" \
\
"ldr r6, [r0] \n\t" \
"adds r10, r6 \n\t" \
"adcs r14, #0 \n\t" \
/* skip past already-loaded (r4, r5) */ \
"ldr r7, [r1], #8 \n\t" \
"ldr r8, [r2], #8 \n\t" \
"mov r9, #0 \n\t" \
"umull r11, r12, r4, r8 \n\t" \
"adds r10, r11 \n\t" \
"adcs r14, r12 \n\t" \
"adc r9, #0 \n\t" \
"umull r11, r12, r5, r7 \n\t" \
"adds r10, r11 \n\t" \
"adcs r14, r12 \n\t" \
"adc r9, #0 \n\t" \
"str r10, [r0], #4 \n\t" \
\
"umull r11, r12, r4, r5 \n\t" \
"adds r11, r14 \n\t" \
"adc r12, r9 \n\t" \
"stmia r0!, {r11, r12} \n\t"
#define FAST_MULT_ASM_6_TO_7 \
"cmp r3, #6 \n\t" \
"beq 1f \n\t" \
\
/* r4 = left high, r5 = right high */ \
"ldr r4, [r1] \n\t" \
"ldr r5, [r2] \n\t" \
\
"sub r0, #24 \n\t" \
"sub r1, #24 \n\t" \
"sub r2, #24 \n\t" \
\
"ldr r6, [r0] \n\t" \
"ldr r7, [r1], #4 \n\t" \
"ldr r8, [r2], #4 \n\t" \
"mov r14, #0 \n\t" \
"umull r9, r10, r4, r8 \n\t" \
"umull r11, r12, r5, r7 \n\t" \
"adds r9, r6 \n\t" \
"adc r10, #0 \n\t" \
"adds r9, r11 \n\t" \
"adcs r10, r12 \n\t" \
"adc r14, #0 \n\t" \
"str r9, [r0], #4 \n\t" \
\
"ldr r6, [r0] \n\t" \
"adds r10, r6 \n\t" \
"adcs r14, #0 \n\t" \
"ldr r7, [r1], #4 \n\t" \
"ldr r8, [r2], #4 \n\t" \
"mov r9, #0 \n\t" \
"umull r11, r12, r4, r8 \n\t" \
"adds r10, r11 \n\t" \
"adcs r14, r12 \n\t" \
"adc r9, #0 \n\t" \
"umull r11, r12, r5, r7 \n\t" \
"adds r10, r11 \n\t" \
"adcs r14, r12 \n\t" \
"adc r9, #0 \n\t" \
"str r10, [r0], #4 \n\t" \
\
"ldr r6, [r0] \n\t" \
"adds r14, r6 \n\t" \
"adcs r9, #0 \n\t" \
"ldr r7, [r1], #4 \n\t" \
"ldr r8, [r2], #4 \n\t" \
"mov r10, #0 \n\t" \
"umull r11, r12, r4, r8 \n\t" \
"adds r14, r11 \n\t" \
"adcs r9, r12 \n\t" \
"adc r10, #0 \n\t" \
"umull r11, r12, r5, r7 \n\t" \
"adds r14, r11 \n\t" \
"adcs r9, r12 \n\t" \
"adc r10, #0 \n\t" \
"str r14, [r0], #4 \n\t" \
\
"ldr r6, [r0] \n\t" \
"adds r9, r6 \n\t" \
"adcs r10, #0 \n\t" \
"ldr r7, [r1], #4 \n\t" \
"ldr r8, [r2], #4 \n\t" \
"mov r14, #0 \n\t" \
"umull r11, r12, r4, r8 \n\t" \
"adds r9, r11 \n\t" \
"adcs r10, r12 \n\t" \
"adc r14, #0 \n\t" \
"umull r11, r12, r5, r7 \n\t" \
"adds r9, r11 \n\t" \
"adcs r10, r12 \n\t" \
"adc r14, #0 \n\t" \
"str r9, [r0], #4 \n\t" \
\
"ldr r6, [r0] \n\t" \
"adds r10, r6 \n\t" \
"adcs r14, #0 \n\t" \
"ldr r7, [r1], #4 \n\t" \
"ldr r8, [r2], #4 \n\t" \
"mov r9, #0 \n\t" \
"umull r11, r12, r4, r8 \n\t" \
"adds r10, r11 \n\t" \
"adcs r14, r12 \n\t" \
"adc r9, #0 \n\t" \
"umull r11, r12, r5, r7 \n\t" \
"adds r10, r11 \n\t" \
"adcs r14, r12 \n\t" \
"adc r9, #0 \n\t" \
"str r10, [r0], #4 \n\t" \
\
"ldr r6, [r0] \n\t" \
"adds r14, r6 \n\t" \
"adcs r9, #0 \n\t" \
/* skip past already-loaded (r4, r5) */ \
"ldr r7, [r1], #8 \n\t" \
"ldr r8, [r2], #8 \n\t" \
"mov r10, #0 \n\t" \
"umull r11, r12, r4, r8 \n\t" \
"adds r14, r11 \n\t" \
"adcs r9, r12 \n\t" \
"adc r10, #0 \n\t" \
"umull r11, r12, r5, r7 \n\t" \
"adds r14, r11 \n\t" \
"adcs r9, r12 \n\t" \
"adc r10, #0 \n\t" \
"str r14, [r0], #4 \n\t" \
\
"umull r11, r12, r4, r5 \n\t" \
"adds r11, r9 \n\t" \
"adc r12, r10 \n\t" \
"stmia r0!, {r11, r12} \n\t"
#define FAST_MULT_ASM_7_TO_8 \
"cmp r3, #7 \n\t" \
"beq 1f \n\t" \
\
/* r4 = left high, r5 = right high */ \
"ldr r4, [r1] \n\t" \
"ldr r5, [r2] \n\t" \
\
"sub r0, #28 \n\t" \
"sub r1, #28 \n\t" \
"sub r2, #28 \n\t" \
\
"ldr r6, [r0] \n\t" \
"ldr r7, [r1], #4 \n\t" \
"ldr r8, [r2], #4 \n\t" \
"mov r14, #0 \n\t" \
"umull r9, r10, r4, r8 \n\t" \
"umull r11, r12, r5, r7 \n\t" \
"adds r9, r6 \n\t" \
"adc r10, #0 \n\t" \
"adds r9, r11 \n\t" \
"adcs r10, r12 \n\t" \
"adc r14, #0 \n\t" \
"str r9, [r0], #4 \n\t" \
\
"ldr r6, [r0] \n\t" \
"adds r10, r6 \n\t" \
"adcs r14, #0 \n\t" \
"ldr r7, [r1], #4 \n\t" \
"ldr r8, [r2], #4 \n\t" \
"mov r9, #0 \n\t" \
"umull r11, r12, r4, r8 \n\t" \
"adds r10, r11 \n\t" \
"adcs r14, r12 \n\t" \
"adc r9, #0 \n\t" \
"umull r11, r12, r5, r7 \n\t" \
"adds r10, r11 \n\t" \
"adcs r14, r12 \n\t" \
"adc r9, #0 \n\t" \
"str r10, [r0], #4 \n\t" \
\
"ldr r6, [r0] \n\t" \
"adds r14, r6 \n\t" \
"adcs r9, #0 \n\t" \
"ldr r7, [r1], #4 \n\t" \
"ldr r8, [r2], #4 \n\t" \
"mov r10, #0 \n\t" \
"umull r11, r12, r4, r8 \n\t" \
"adds r14, r11 \n\t" \
"adcs r9, r12 \n\t" \
"adc r10, #0 \n\t" \
"umull r11, r12, r5, r7 \n\t" \
"adds r14, r11 \n\t" \
"adcs r9, r12 \n\t" \
"adc r10, #0 \n\t" \
"str r14, [r0], #4 \n\t" \
\
"ldr r6, [r0] \n\t" \
"adds r9, r6 \n\t" \
"adcs r10, #0 \n\t" \
"ldr r7, [r1], #4 \n\t" \
"ldr r8, [r2], #4 \n\t" \
"mov r14, #0 \n\t" \
"umull r11, r12, r4, r8 \n\t" \
"adds r9, r11 \n\t" \
"adcs r10, r12 \n\t" \
"adc r14, #0 \n\t" \
"umull r11, r12, r5, r7 \n\t" \
"adds r9, r11 \n\t" \
"adcs r10, r12 \n\t" \
"adc r14, #0 \n\t" \
"str r9, [r0], #4 \n\t" \
\
"ldr r6, [r0] \n\t" \
"adds r10, r6 \n\t" \
"adcs r14, #0 \n\t" \
"ldr r7, [r1], #4 \n\t" \
"ldr r8, [r2], #4 \n\t" \
"mov r9, #0 \n\t" \
"umull r11, r12, r4, r8 \n\t" \
"adds r10, r11 \n\t" \
"adcs r14, r12 \n\t" \
"adc r9, #0 \n\t" \
"umull r11, r12, r5, r7 \n\t" \
"adds r10, r11 \n\t" \
"adcs r14, r12 \n\t" \
"adc r9, #0 \n\t" \
"str r10, [r0], #4 \n\t" \
\
"ldr r6, [r0] \n\t" \
"adds r14, r6 \n\t" \
"adcs r9, #0 \n\t" \
"ldr r7, [r1], #4 \n\t" \
"ldr r8, [r2], #4 \n\t" \
"mov r10, #0 \n\t" \
"umull r11, r12, r4, r8 \n\t" \
"adds r14, r11 \n\t" \
"adcs r9, r12 \n\t" \
"adc r10, #0 \n\t" \
"umull r11, r12, r5, r7 \n\t" \
"adds r14, r11 \n\t" \
"adcs r9, r12 \n\t" \
"adc r10, #0 \n\t" \
"str r14, [r0], #4 \n\t" \
\
"ldr r6, [r0] \n\t" \
"adds r9, r6 \n\t" \
"adcs r10, #0 \n\t" \
/* skip past already-loaded (r4, r5) */ \
"ldr r7, [r1], #8 \n\t" \
"ldr r8, [r2], #8 \n\t" \
"mov r14, #0 \n\t" \
"umull r11, r12, r4, r8 \n\t" \
"adds r9, r11 \n\t" \
"adcs r10, r12 \n\t" \
"adc r14, #0 \n\t" \
"umull r11, r12, r5, r7 \n\t" \
"adds r9, r11 \n\t" \
"adcs r10, r12 \n\t" \
"adc r14, #0 \n\t" \
"str r9, [r0], #4 \n\t" \
\
"umull r11, r12, r4, r5 \n\t" \
"adds r11, r10 \n\t" \
"adc r12, r14 \n\t" \
"stmia r0!, {r11, r12} \n\t"
#if (uECC_PLATFORM != uECC_arm_thumb)
uECC_VLI_API void uECC_vli_mult(uint32_t *result,
const uint32_t *left,
const uint32_t *right,
wordcount_t num_words) {
register uint32_t *r0 __asm__("r0") = result;
register const uint32_t *r1 __asm__("r1") = left;
register const uint32_t *r2 __asm__("r2") = right;
register uint32_t r3 __asm__("r3") = num_words;
__asm__ volatile (
".syntax unified \n\t"
"push {r3} \n\t"
#if (uECC_MIN_WORDS == 5)
FAST_MULT_ASM_5
"pop {r3} \n\t"
#if (uECC_MAX_WORDS > 5)
FAST_MULT_ASM_5_TO_6
#endif
#if (uECC_MAX_WORDS > 6)
FAST_MULT_ASM_6_TO_7
#endif
#if (uECC_MAX_WORDS > 7)
FAST_MULT_ASM_7_TO_8
#endif
#elif (uECC_MIN_WORDS == 6)
FAST_MULT_ASM_6
"pop {r3} \n\t"
#if (uECC_MAX_WORDS > 6)
FAST_MULT_ASM_6_TO_7
#endif
#if (uECC_MAX_WORDS > 7)
FAST_MULT_ASM_7_TO_8
#endif
#elif (uECC_MIN_WORDS == 7)
FAST_MULT_ASM_7
"pop {r3} \n\t"
#if (uECC_MAX_WORDS > 7)
FAST_MULT_ASM_7_TO_8
#endif
#elif (uECC_MIN_WORDS == 8)
FAST_MULT_ASM_8
"pop {r3} \n\t"
#endif
"1: \n\t"
RESUME_SYNTAX
: "+r" (r0), "+r" (r1), "+r" (r2)
: "r" (r3)
: "r4", "r5", "r6", "r7", "r8", "r9", "r10", "r11", "r12", "r14", "cc", "memory"
);
}
#define asm_mult 1
#if uECC_SQUARE_FUNC
#define FAST_SQUARE_ASM_5_TO_6 \
"cmp r2, #5 \n\t" \
"beq 1f \n\t" \
\
/* r3 = high */ \
"ldr r3, [r1] \n\t" \
\
"sub r0, #20 \n\t" \
"sub r1, #20 \n\t" \
\
/* Do off-center multiplication */ \
"ldr r14, [r1], #4 \n\t" \
"umull r4, r5, r3, r14 \n\t" \
"ldr r14, [r1], #4 \n\t" \
"umull r7, r6, r3, r14 \n\t" \
"adds r5, r7 \n\t" \
"ldr r14, [r1], #4 \n\t" \
"umull r8, r7, r3, r14 \n\t" \
"adcs r6, r8 \n\t" \
"ldr r14, [r1], #4 \n\t" \
"umull r9, r8, r3, r14 \n\t" \
"adcs r7, r9 \n\t" \
/* Skip already-loaded r3 */ \
"ldr r14, [r1], #8 \n\t" \
"umull r10, r9, r3, r14 \n\t" \
"adcs r8, r10 \n\t" \
"adcs r9, #0 \n\t" \
\
/* Multiply by 2 */ \
"mov r10, #0 \n\t" \
"adds r4, r4 \n\t" \
"adcs r5, r5 \n\t" \
"adcs r6, r6 \n\t" \
"adcs r7, r7 \n\t" \
"adcs r8, r8 \n\t" \
"adcs r9, r9 \n\t" \
"adcs r10, #0 \n\t" \
\
/* Add into previous */ \
"ldr r14, [r0] \n\t" \
"adds r4, r14 \n\t" \
"str r4, [r0], #4 \n\t" \
"ldr r14, [r0] \n\t" \
"adcs r5, r14 \n\t" \
"str r5, [r0], #4 \n\t" \
"ldr r14, [r0] \n\t" \
"adcs r6, r14 \n\t" \
"str r6, [r0], #4 \n\t" \
"ldr r14, [r0] \n\t" \
"adcs r7, r14 \n\t" \
"str r7, [r0], #4 \n\t" \
"ldr r14, [r0] \n\t" \
"adcs r8, r14 \n\t" \
"str r8, [r0], #4 \n\t" \
"adcs r9, #0 \n\t" \
"adcs r10, #0 \n\t" \
\
/* Perform center multiplication */ \
"umull r4, r5, r3, r3 \n\t" \
"adds r4, r9 \n\t" \
"adc r5, r10 \n\t" \
"stmia r0!, {r4, r5} \n\t"
#define FAST_SQUARE_ASM_6_TO_7 \
"cmp r2, #6 \n\t" \
"beq 1f \n\t" \
\
/* r3 = high */ \
"ldr r3, [r1] \n\t" \
\
"sub r0, #24 \n\t" \
"sub r1, #24 \n\t" \
\
/* Do off-center multiplication */ \
"ldr r14, [r1], #4 \n\t" \
"umull r4, r5, r3, r14 \n\t" \
"ldr r14, [r1], #4 \n\t" \
"umull r7, r6, r3, r14 \n\t" \
"adds r5, r7 \n\t" \
"ldr r14, [r1], #4 \n\t" \
"umull r8, r7, r3, r14 \n\t" \
"adcs r6, r8 \n\t" \
"ldr r14, [r1], #4 \n\t" \
"umull r9, r8, r3, r14 \n\t" \
"adcs r7, r9 \n\t" \
"ldr r14, [r1], #4 \n\t" \
"umull r10, r9, r3, r14 \n\t" \
"adcs r8, r10 \n\t" \
/* Skip already-loaded r3 */ \
"ldr r14, [r1], #8 \n\t" \
"umull r11, r10, r3, r14 \n\t" \
"adcs r9, r11 \n\t" \
"adcs r10, #0 \n\t" \
\
/* Multiply by 2 */ \
"mov r11, #0 \n\t" \
"adds r4, r4 \n\t" \
"adcs r5, r5 \n\t" \
"adcs r6, r6 \n\t" \
"adcs r7, r7 \n\t" \
"adcs r8, r8 \n\t" \
"adcs r9, r9 \n\t" \
"adcs r10, r10 \n\t" \
"adcs r11, #0 \n\t" \
\
/* Add into previous */ \
"ldr r14, [r0] \n\t" \
"adds r4, r14 \n\t" \
"str r4, [r0], #4 \n\t" \
"ldr r14, [r0] \n\t" \
"adcs r5, r14 \n\t" \
"str r5, [r0], #4 \n\t" \
"ldr r14, [r0] \n\t" \
"adcs r6, r14 \n\t" \
"str r6, [r0], #4 \n\t" \
"ldr r14, [r0] \n\t" \
"adcs r7, r14 \n\t" \
"str r7, [r0], #4 \n\t" \
"ldr r14, [r0] \n\t" \
"adcs r8, r14 \n\t" \
"str r8, [r0], #4 \n\t" \
"ldr r14, [r0] \n\t" \
"adcs r9, r14 \n\t" \
"str r9, [r0], #4 \n\t" \
"adcs r10, #0 \n\t" \
"adcs r11, #0 \n\t" \
\
/* Perform center multiplication */ \
"umull r4, r5, r3, r3 \n\t" \
"adds r4, r10 \n\t" \
"adc r5, r11 \n\t" \
"stmia r0!, {r4, r5} \n\t"
#define FAST_SQUARE_ASM_7_TO_8 \
"cmp r2, #7 \n\t" \
"beq 1f \n\t" \
\
/* r3 = high */ \
"ldr r3, [r1] \n\t" \
\
"sub r0, #28 \n\t" \
"sub r1, #28 \n\t" \
\
/* Do off-center multiplication */ \
"ldr r14, [r1], #4 \n\t" \
"umull r4, r5, r3, r14 \n\t" \
"ldr r14, [r1], #4 \n\t" \
"umull r7, r6, r3, r14 \n\t" \
"adds r5, r7 \n\t" \
"ldr r14, [r1], #4 \n\t" \
"umull r8, r7, r3, r14 \n\t" \
"adcs r6, r8 \n\t" \
"ldr r14, [r1], #4 \n\t" \
"umull r9, r8, r3, r14 \n\t" \
"adcs r7, r9 \n\t" \
"ldr r14, [r1], #4 \n\t" \
"umull r10, r9, r3, r14 \n\t" \
"adcs r8, r10 \n\t" \
"ldr r14, [r1], #4 \n\t" \
"umull r11, r10, r3, r14 \n\t" \
"adcs r9, r11 \n\t" \
/* Skip already-loaded r3 */ \
"ldr r14, [r1], #8 \n\t" \
"umull r12, r11, r3, r14 \n\t" \
"adcs r10, r12 \n\t" \
"adcs r11, #0 \n\t" \
\
/* Multiply by 2 */ \
"mov r12, #0 \n\t" \
"adds r4, r4 \n\t" \
"adcs r5, r5 \n\t" \
"adcs r6, r6 \n\t" \
"adcs r7, r7 \n\t" \
"adcs r8, r8 \n\t" \
"adcs r9, r9 \n\t" \
"adcs r10, r10 \n\t" \
"adcs r11, r11 \n\t" \
"adcs r12, #0 \n\t" \
\
/* Add into previous */ \
"ldr r14, [r0] \n\t" \
"adds r4, r14 \n\t" \
"str r4, [r0], #4 \n\t" \
"ldr r14, [r0] \n\t" \
"adcs r5, r14 \n\t" \
"str r5, [r0], #4 \n\t" \
"ldr r14, [r0] \n\t" \
"adcs r6, r14 \n\t" \
"str r6, [r0], #4 \n\t" \
"ldr r14, [r0] \n\t" \
"adcs r7, r14 \n\t" \
"str r7, [r0], #4 \n\t" \
"ldr r14, [r0] \n\t" \
"adcs r8, r14 \n\t" \
"str r8, [r0], #4 \n\t" \
"ldr r14, [r0] \n\t" \
"adcs r9, r14 \n\t" \
"str r9, [r0], #4 \n\t" \
"ldr r14, [r0] \n\t" \
"adcs r10, r14 \n\t" \
"str r10, [r0], #4 \n\t" \
"adcs r11, #0 \n\t" \
"adcs r12, #0 \n\t" \
\
/* Perform center multiplication */ \
"umull r4, r5, r3, r3 \n\t" \
"adds r4, r11 \n\t" \
"adc r5, r12 \n\t" \
"stmia r0!, {r4, r5} \n\t"
uECC_VLI_API void uECC_vli_square(uECC_word_t *result,
const uECC_word_t *left,
wordcount_t num_words) {
register uint32_t *r0 __asm__("r0") = result;
register const uint32_t *r1 __asm__("r1") = left;
register uint32_t r2 __asm__("r2") = num_words;
__asm__ volatile (
".syntax unified \n\t"
"push {r1, r2} \n\t"
#if (uECC_MIN_WORDS == 5)
FAST_SQUARE_ASM_5
"pop {r1, r2} \n\t"
#if (uECC_MAX_WORDS > 5)
"add r1, #20 \n\t"
FAST_SQUARE_ASM_5_TO_6
#endif
#if (uECC_MAX_WORDS > 6)
FAST_SQUARE_ASM_6_TO_7
#endif
#if (uECC_MAX_WORDS > 7)
FAST_SQUARE_ASM_7_TO_8
#endif
#elif (uECC_MIN_WORDS == 6)
FAST_SQUARE_ASM_6
"pop {r1, r2} \n\t"
#if (uECC_MAX_WORDS > 6)
"add r1, #24 \n\t"
FAST_SQUARE_ASM_6_TO_7
#endif
#if (uECC_MAX_WORDS > 7)
FAST_SQUARE_ASM_7_TO_8
#endif
#elif (uECC_MIN_WORDS == 7)
FAST_SQUARE_ASM_7
"pop {r1, r2} \n\t"
#if (uECC_MAX_WORDS > 7)
"add r1, #28 \n\t"
FAST_SQUARE_ASM_7_TO_8
#endif
#elif (uECC_MIN_WORDS == 8)
FAST_SQUARE_ASM_8
"pop {r1, r2} \n\t"
#endif
"1: \n\t"
RESUME_SYNTAX
: "+r" (r0), "+r" (r1)
: "r" (r2)
: "r3", "r4", "r5", "r6", "r7", "r8", "r9", "r10", "r11", "r12", "r14", "cc", "memory"
);
}
#define asm_square 1
#endif /* uECC_SQUARE_FUNC */
#endif /* uECC_PLATFORM != uECC_arm_thumb */
#endif /* (uECC_OPTIMIZATION_LEVEL >= 3) */
/* ---- "Small" implementations ---- */
#if !asm_add
uECC_VLI_API uECC_word_t uECC_vli_add(uECC_word_t *result,
const uECC_word_t *left,
const uECC_word_t *right,
wordcount_t num_words) {
uint32_t carry = 0;
uint32_t left_word;
uint32_t right_word;
__asm__ volatile (
".syntax unified \n\t"
"1: \n\t"
"ldmia %[lptr]!, {%[left]} \n\t" /* Load left word. */
"ldmia %[rptr]!, {%[right]} \n\t" /* Load right word. */
"lsrs %[carry], #1 \n\t" /* Set up carry flag (carry = 0 after this). */
"adcs %[left], %[right] \n\t" /* Add with carry. */
"adcs %[carry], %[carry] \n\t" /* Store carry bit. */
"stmia %[dptr]!, {%[left]} \n\t" /* Store result word. */
"subs %[ctr], #1 \n\t" /* Decrement counter. */
"bne 1b \n\t" /* Loop until counter == 0. */
RESUME_SYNTAX
: [dptr] REG_RW (result), [lptr] REG_RW (left), [rptr] REG_RW (right),
[ctr] REG_RW (num_words), [carry] REG_RW (carry),
[left] REG_WRITE (left_word), [right] REG_WRITE (right_word)
:
: "cc", "memory"
);
return carry;
}
#define asm_add 1
#endif
#if !asm_sub
uECC_VLI_API uECC_word_t uECC_vli_sub(uECC_word_t *result,
const uECC_word_t *left,
const uECC_word_t *right,
wordcount_t num_words) {
uint32_t carry = 1; /* carry = 1 initially (means don't borrow) */
uint32_t left_word;
uint32_t right_word;
__asm__ volatile (
".syntax unified \n\t"
"1: \n\t"
"ldmia %[lptr]!, {%[left]} \n\t" /* Load left word. */
"ldmia %[rptr]!, {%[right]} \n\t" /* Load right word. */
"lsrs %[carry], #1 \n\t" /* Set up carry flag (carry = 0 after this). */
"sbcs %[left], %[right] \n\t" /* Subtract with borrow. */
"adcs %[carry], %[carry] \n\t" /* Store carry bit. */
"stmia %[dptr]!, {%[left]} \n\t" /* Store result word. */
"subs %[ctr], #1 \n\t" /* Decrement counter. */
"bne 1b \n\t" /* Loop until counter == 0. */
RESUME_SYNTAX
: [dptr] REG_RW (result), [lptr] REG_RW (left), [rptr] REG_RW (right),
[ctr] REG_RW (num_words), [carry] REG_RW (carry),
[left] REG_WRITE (left_word), [right] REG_WRITE (right_word)
:
: "cc", "memory"
);
return !carry;
}
#define asm_sub 1
#endif
#if !asm_mult
uECC_VLI_API void uECC_vli_mult(uECC_word_t *result,
const uECC_word_t *left,
const uECC_word_t *right,
wordcount_t num_words) {
#if (uECC_PLATFORM != uECC_arm_thumb)
uint32_t c0 = 0;
uint32_t c1 = 0;
uint32_t c2 = 0;
uint32_t k = 0;
uint32_t i;
uint32_t t0, t1;
__asm__ volatile (
".syntax unified \n\t"
"1: \n\t" /* outer loop (k < num_words) */
"movs %[i], #0 \n\t" /* i = 0 */
"b 3f \n\t"
"2: \n\t" /* outer loop (k >= num_words) */
"movs %[i], %[k] \n\t" /* i = k */
"subs %[i], %[last_word] \n\t" /* i = k - (num_words - 1) (times 4) */
"3: \n\t" /* inner loop */
"subs %[t0], %[k], %[i] \n\t" /* t0 = k-i */
"ldr %[t1], [%[right], %[t0]] \n\t" /* t1 = right[k - i] */
"ldr %[t0], [%[left], %[i]] \n\t" /* t0 = left[i] */
"umull %[t0], %[t1], %[t0], %[t1] \n\t" /* (t0, t1) = left[i] * right[k - i] */
"adds %[c0], %[t0] \n\t" /* add low word to c0 */
"adcs %[c1], %[t1] \n\t" /* add high word to c1, including carry */
"adcs %[c2], #0 \n\t" /* add carry to c2 */
"adds %[i], #4 \n\t" /* i += 4 */
"cmp %[i], %[last_word] \n\t" /* i > (num_words - 1) (times 4)? */
"bgt 4f \n\t" /* if so, exit the loop */
"cmp %[i], %[k] \n\t" /* i <= k? */
"ble 3b \n\t" /* if so, continue looping */
"4: \n\t" /* end inner loop */
"str %[c0], [%[result], %[k]] \n\t" /* result[k] = c0 */
"mov %[c0], %[c1] \n\t" /* c0 = c1 */
"mov %[c1], %[c2] \n\t" /* c1 = c2 */
"movs %[c2], #0 \n\t" /* c2 = 0 */
"adds %[k], #4 \n\t" /* k += 4 */
"cmp %[k], %[last_word] \n\t" /* k <= (num_words - 1) (times 4) ? */
"ble 1b \n\t" /* if so, loop back, start with i = 0 */
"cmp %[k], %[last_word], lsl #1 \n\t" /* k <= (num_words * 2 - 2) (times 4) ? */
"ble 2b \n\t" /* if so, loop back, start with i = (k + 1) - num_words */
/* end outer loop */
"str %[c0], [%[result], %[k]] \n\t" /* result[num_words * 2 - 1] = c0 */
RESUME_SYNTAX
: [c0] "+r" (c0), [c1] "+r" (c1), [c2] "+r" (c2),
[k] "+r" (k), [i] "=&r" (i), [t0] "=&r" (t0), [t1] "=&r" (t1)
: [result] "r" (result), [left] "r" (left), [right] "r" (right),
[last_word] "r" ((num_words - 1) * 4)
: "cc", "memory"
);
#else /* Thumb-1 */
register uint32_t *r0 __asm__("r0") = result;
register const uint32_t *r1 __asm__("r1") = left;
register const uint32_t *r2 __asm__("r2") = right;
__asm__ volatile (
".syntax unified \n\t"
"movs r3, #0 \n\t" /* c0 = 0 */
"movs r4, #0 \n\t" /* c1 = 0 */
"movs r5, #0 \n\t" /* c2 = 0 */
"movs r6, #0 \n\t" /* k = 0 */
"push {r0} \n\t" /* keep result on the stack */
"1: \n\t" /* outer loop (k < num_words) */
"movs r7, #0 \n\t" /* r7 = i = 0 */
"b 3f \n\t"
"2: \n\t" /* outer loop (k >= num_words) */
"movs r7, r6 \n\t" /* r7 = k */
"subs r7, %[last_word] \n\t" /* r7 = i = k - (num_words - 1) (times 4) */
"3: \n\t" /* inner loop */
"push {r3, r4, r5, r6} \n\t" /* push things, r3 (c0) is at the top of stack. */
"subs r0, r6, r7 \n\t" /* r0 = k - i */
"ldr r4, [r2, r0] \n\t" /* r4 = right[k - i] */
"ldr r0, [r1, r7] \n\t" /* r0 = left[i] */
"lsrs r3, r0, #16 \n\t" /* r3 = a1 */
"uxth r0, r0 \n\t" /* r0 = a0 */
"lsrs r5, r4, #16 \n\t" /* r5 = b1 */
"uxth r4, r4 \n\t" /* r4 = b0 */
"movs r6, r3 \n\t" /* r6 = a1 */
"muls r6, r5, r6 \n\t" /* r6 = a1 * b1 */
"muls r3, r4, r3 \n\t" /* r3 = b0 * a1 */
"muls r5, r0, r5 \n\t" /* r5 = a0 * b1 */
"muls r0, r4, r0 \n\t" /* r0 = a0 * b0 */
"movs r4, #0 \n\t" /* r4 = 0 */
"adds r3, r5 \n\t" /* r3 = b0 * a1 + a0 * b1 */
"adcs r4, r4 \n\t" /* r4 = carry */
"lsls r4, #16 \n\t" /* r4 = carry << 16 */
"adds r6, r4 \n\t" /* r6 = a1 * b1 + carry */
"lsls r4, r3, #16 \n\t" /* r4 = (b0 * a1 + a0 * b1) << 16 */
"lsrs r3, #16 \n\t" /* r3 = (b0 * a1 + a0 * b1) >> 16 */
"adds r0, r4 \n\t" /* r0 = low word = a0 * b0 + ((b0 * a1 + a0 * b1) << 16) */
"adcs r6, r3 \n\t" /* r6 = high word = a1 * b1 + carry + ((b0 * a1 + a0 * b1) >> 16) */
"pop {r3, r4, r5} \n\t" /* r3 = c0, r4 = c1, r5 = c2 */
"adds r3, r0 \n\t" /* add low word to c0 */
"adcs r4, r6 \n\t" /* add high word to c1, including carry */
"movs r0, #0 \n\t" /* r0 = 0 (does not affect carry bit) */
"adcs r5, r0 \n\t" /* add carry to c2 */
"pop {r6} \n\t" /* r6 = k */
"adds r7, #4 \n\t" /* i += 4 */
"cmp r7, %[last_word] \n\t" /* i > (num_words - 1) (times 4)? */
"bgt 4f \n\t" /* if so, exit the loop */
"cmp r7, r6 \n\t" /* i <= k? */
"ble 3b \n\t" /* if so, continue looping */
"4: \n\t" /* end inner loop */
"ldr r0, [sp, #0] \n\t" /* r0 = result */
"str r3, [r0, r6] \n\t" /* result[k] = c0 */
"mov r3, r4 \n\t" /* c0 = c1 */
"mov r4, r5 \n\t" /* c1 = c2 */
"movs r5, #0 \n\t" /* c2 = 0 */
"adds r6, #4 \n\t" /* k += 4 */
"cmp r6, %[last_word] \n\t" /* k <= (num_words - 1) (times 4) ? */
"ble 1b \n\t" /* if so, loop back, start with i = 0 */
"cmp r6, %[lw2] \n\t" /* k <= (num_words * 2 - 2) (times 4) ? */
"ble 2b \n\t" /* if so, loop back, start with i = (k + 1) - num_words */
/* end outer loop */
"str r3, [r0, r6] \n\t" /* result[num_words * 2 - 1] = c0 */
"pop {r0} \n\t" /* pop result off the stack */
".syntax divided \n\t"
:
: [r0] "l" (r0), [r1] "l" (r1), [r2] "l" (r2),
[last_word] "r" ((num_words - 1) * 4), [lw2] "r" ((num_words - 1) * 4 * 2)
: "r3", "r4", "r5", "r6", "r7", "cc", "memory"
);
#endif
}
#define asm_mult 1
#endif
#if uECC_SQUARE_FUNC
#if !asm_square
uECC_VLI_API void uECC_vli_square(uECC_word_t *result,
const uECC_word_t *left,
wordcount_t num_words) {
#if (uECC_PLATFORM != uECC_arm_thumb)
uint32_t c0 = 0;
uint32_t c1 = 0;
uint32_t c2 = 0;
uint32_t k = 0;
uint32_t i, tt;
uint32_t t0, t1;
__asm__ volatile (
".syntax unified \n\t"
"1: \n\t" /* outer loop (k < num_words) */
"movs %[i], #0 \n\t" /* i = 0 */
"b 3f \n\t"
"2: \n\t" /* outer loop (k >= num_words) */
"movs %[i], %[k] \n\t" /* i = k */
"subs %[i], %[last_word] \n\t" /* i = k - (num_words - 1) (times 4) */
"3: \n\t" /* inner loop */
"subs %[tt], %[k], %[i] \n\t" /* tt = k-i */
"ldr %[t1], [%[left], %[tt]] \n\t" /* t1 = left[k - i] */
"ldr %[t0], [%[left], %[i]] \n\t" /* t0 = left[i] */
"umull %[t0], %[t1], %[t0], %[t1] \n\t" /* (t0, t1) = left[i] * right[k - i] */
"cmp %[i], %[tt] \n\t" /* (i < k - i) ? */
"bge 4f \n\t" /* if i >= k - i, skip */
"lsls %[t1], #1 \n\t" /* high word << 1 */
"adc %[c2], #0 \n\t" /* add carry bit to c2 */
"lsls %[t0], #1 \n\t" /* low word << 1 */
"adc %[t1], #0 \n\t" /* add carry bit to high word */
"4: \n\t"
"adds %[c0], %[t0] \n\t" /* add low word to c0 */
"adcs %[c1], %[t1] \n\t" /* add high word to c1, including carry */
"adc %[c2], #0 \n\t" /* add carry to c2 */
"adds %[i], #4 \n\t" /* i += 4 */
"cmp %[i], %[k] \n\t" /* i >= k? */
"bge 5f \n\t" /* if so, exit the loop */
"subs %[tt], %[k], %[i] \n\t" /* tt = k - i */
"cmp %[i], %[tt] \n\t" /* i <= k - i? */
"ble 3b \n\t" /* if so, continue looping */
"5: \n\t" /* end inner loop */
"str %[c0], [%[result], %[k]] \n\t" /* result[k] = c0 */
"mov %[c0], %[c1] \n\t" /* c0 = c1 */
"mov %[c1], %[c2] \n\t" /* c1 = c2 */
"movs %[c2], #0 \n\t" /* c2 = 0 */
"adds %[k], #4 \n\t" /* k += 4 */
"cmp %[k], %[last_word] \n\t" /* k <= (num_words - 1) (times 4) ? */
"ble 1b \n\t" /* if so, loop back, start with i = 0 */
"cmp %[k], %[last_word], lsl #1 \n\t" /* k <= (num_words * 2 - 2) (times 4) ? */
"ble 2b \n\t" /* if so, loop back, start with i = (k + 1) - num_words */
/* end outer loop */
"str %[c0], [%[result], %[k]] \n\t" /* result[num_words * 2 - 1] = c0 */
RESUME_SYNTAX
: [c0] "+r" (c0), [c1] "+r" (c1), [c2] "+r" (c2),
[k] "+r" (k), [i] "=&r" (i), [tt] "=&r" (tt), [t0] "=&r" (t0), [t1] "=&r" (t1)
: [result] "r" (result), [left] "r" (left), [last_word] "r" ((num_words - 1) * 4)
: "cc", "memory"
);
#else
register uint32_t *r0 __asm__("r0") = result;
register const uint32_t *r1 __asm__("r1") = left;
__asm__ volatile (
".syntax unified \n\t"
"movs r2, #0 \n\t" /* c0 = 0 */
"movs r3, #0 \n\t" /* c1 = 0 */
"movs r4, #0 \n\t" /* c2 = 0 */
"movs r5, #0 \n\t" /* k = 0 */
"push {r0} \n\t" /* keep result on the stack */
"1: \n\t" /* outer loop (k < num_words) */
"movs r6, #0 \n\t" /* r6 = i = 0 */
"b 3f \n\t"
"2: \n\t" /* outer loop (k >= num_words) */
"movs r6, r5 \n\t" /* r6 = k */
"subs r6, %[last_word] \n\t" /* r6 = i = k - (num_words - 1) (times 4) */
"3: \n\t" /* inner loop */
"push {r2, r3, r4, r5} \n\t" /* push things, r2 (c0) is at the top of stack. */
"subs r7, r5, r6 \n\t" /* r7 = k - i */
"ldr r3, [r1, r7] \n\t" /* r3 = left[k - i] */
"ldr r0, [r1, r6] \n\t" /* r0 = left[i] */
"lsrs r2, r0, #16 \n\t" /* r2 = a1 */
"uxth r0, r0 \n\t" /* r0 = a0 */
"lsrs r4, r3, #16 \n\t" /* r4 = b1 */
"uxth r3, r3 \n\t" /* r3 = b0 */
"movs r5, r2 \n\t" /* r5 = a1 */
"muls r5, r4, r5 \n\t" /* r5 = a1 * b1 */
"muls r2, r3, r2 \n\t" /* r2 = b0 * a1 */
"muls r4, r0, r4 \n\t" /* r4 = a0 * b1 */
"muls r0, r3, r0 \n\t" /* r0 = a0 * b0 */
"movs r3, #0 \n\t" /* r3 = 0 */
"adds r2, r4 \n\t" /* r2 = b0 * a1 + a0 * b1 */
"adcs r3, r3 \n\t" /* r3 = carry */
"lsls r3, #16 \n\t" /* r3 = carry << 16 */
"adds r5, r3 \n\t" /* r5 = a1 * b1 + carry */
"lsls r3, r2, #16 \n\t" /* r3 = (b0 * a1 + a0 * b1) << 16 */
"lsrs r2, #16 \n\t" /* r2 = (b0 * a1 + a0 * b1) >> 16 */
"adds r0, r3 \n\t" /* r0 = low word = a0 * b0 + ((b0 * a1 + a0 * b1) << 16) */
"adcs r5, r2 \n\t" /* r5 = high word = a1 * b1 + carry + ((b0 * a1 + a0 * b1) >> 16) */
"movs r3, #0 \n\t" /* r3 = 0 */
"cmp r6, r7 \n\t" /* (i < k - i) ? */
"mov r7, r3 \n\t" /* r7 = 0 (does not affect condition)*/
"bge 4f \n\t" /* if i >= k - i, skip */
"lsls r5, #1 \n\t" /* high word << 1 */
"adcs r7, r3 \n\t" /* r7 = carry bit for c2 */
"lsls r0, #1 \n\t" /* low word << 1 */
"adcs r5, r3 \n\t" /* add carry from shift to high word */
"4: \n\t"
"pop {r2, r3, r4} \n\t" /* r2 = c0, r3 = c1, r4 = c2 */
"adds r2, r0 \n\t" /* add low word to c0 */
"adcs r3, r5 \n\t" /* add high word to c1, including carry */
"movs r0, #0 \n\t" /* r0 = 0 (does not affect carry bit) */
"adcs r4, r0 \n\t" /* add carry to c2 */
"adds r4, r7 \n\t" /* add carry from doubling (if any) */
"pop {r5} \n\t" /* r5 = k */
"adds r6, #4 \n\t" /* i += 4 */
"cmp r6, r5 \n\t" /* i >= k? */
"bge 5f \n\t" /* if so, exit the loop */
"subs r7, r5, r6 \n\t" /* r7 = k - i */
"cmp r6, r7 \n\t" /* i <= k - i? */
"ble 3b \n\t" /* if so, continue looping */
"5: \n\t" /* end inner loop */
"ldr r0, [sp, #0] \n\t" /* r0 = result */
"str r2, [r0, r5] \n\t" /* result[k] = c0 */
"mov r2, r3 \n\t" /* c0 = c1 */
"mov r3, r4 \n\t" /* c1 = c2 */
"movs r4, #0 \n\t" /* c2 = 0 */
"adds r5, #4 \n\t" /* k += 4 */
"cmp r5, %[last_word] \n\t" /* k <= (num_words - 1) (times 4) ? */
"ble 1b \n\t" /* if so, loop back, start with i = 0 */
"cmp r5, %[lw2] \n\t" /* k <= (num_words * 2 - 2) (times 4) ? */
"ble 2b \n\t" /* if so, loop back, start with i = (k + 1) - num_words */
/* end outer loop */
"str r2, [r0, r5] \n\t" /* result[num_words * 2 - 1] = c0 */
"pop {r0} \n\t" /* pop result off the stack */
".syntax divided \n\t"
: [r0] "+l" (r0), [r1] "+l" (r1)
: [last_word] "r" ((num_words - 1) * 4), [lw2] "r" ((num_words - 1) * 4 * 2)
: "r2", "r3", "r4", "r5", "r6", "r7", "cc", "memory"
);
#endif
}
#define asm_square 1
#endif
#endif /* uECC_SQUARE_FUNC */
#endif /* _UECC_ASM_ARM_H_ */