commit 1b1f0a6ae0aacec9dd637d06455555b30f54ba0e
author Ken MacKay <kmackay@gmail.com> Sat Oct 10 21:47:19 2015 -0700
committer Ken MacKay <kmackay@gmail.com> Mon Oct 12 21:29:57 2015 -0700
tree 0574386ce3e06d32ab9e78fd5f21d9967fa0f653
parent c712249e23eca47b9d192367e5233831ddcc95c1

Simplify fast ARM asm for add/sub

asm_arm.inc

diff --git a/asm_arm.inc b/asm_arm.inc
index 7d02b52..572f9da 100644
--- a/asm_arm.inc
+++ b/asm_arm.inc
@@ -51,9 +51,9 @@
                                       wordcount_t num_words) {
 #if (uECC_MAX_WORDS != uECC_MIN_WORDS)
   #if (uECC_PLATFORM == uECC_arm_thumb) || (uECC_PLATFORM == uECC_arm_thumb2)
-    uint32_t jump = ((uECC_MAX_WORDS - num_words) * 4 + 5) * 2 + 1;
+    uint32_t jump = (uECC_MAX_WORDS - num_words) * 4 * 2 + 1;
   #else /* ARM */
-    uint32_t jump = ((uECC_MAX_WORDS - num_words) * 4 + 5) * 4;
+    uint32_t jump = (uECC_MAX_WORDS - num_words) * 4 * 4;
   #endif
 #endif
     uint32_t carry;
@@ -64,7 +64,7 @@
         ".syntax unified \n\t"
         "movs %[carry], #0 \n\t"
     #if (uECC_MAX_WORDS != uECC_MIN_WORDS)
-        "mov %[left], pc \n\t"
+        "adr %[left], 1f \n\t"
         "adds %[jump], %[left] \n\t"
     #endif
         
@@ -76,7 +76,7 @@
     #if (uECC_MAX_WORDS != uECC_MIN_WORDS)
         "bx %[jump] \n\t"
     #endif
-
+        "1: \n\t"
         "ldmia %[lptr]!, {%[left]} \n\t"
         "ldmia %[rptr]!, {%[right]} \n\t"
         "adcs %[left], %[right] \n\t"
@@ -136,9 +136,9 @@
                                       wordcount_t num_words) {
 #if (uECC_MAX_WORDS != uECC_MIN_WORDS)
   #if (uECC_PLATFORM == uECC_arm_thumb) || (uECC_PLATFORM == uECC_arm_thumb2)
-    uint32_t jump = ((uECC_MAX_WORDS - num_words) * 4 + 5) * 2 + 1;
+    uint32_t jump = (uECC_MAX_WORDS - num_words) * 4 * 2 + 1;
   #else /* ARM */
-    uint32_t jump = ((uECC_MAX_WORDS - num_words) * 4 + 5) * 4;
+    uint32_t jump = (uECC_MAX_WORDS - num_words) * 4 * 4;
   #endif
 #endif
     uint32_t carry;
@@ -149,7 +149,7 @@
         ".syntax unified \n\t"
         "movs %[carry], #0 \n\t"
     #if (uECC_MAX_WORDS != uECC_MIN_WORDS)
-        "mov %[left], pc \n\t"
+        "adr %[left], 1f \n\t"
         "adds %[jump], %[left] \n\t"
     #endif
         
@@ -161,7 +161,7 @@
     #if (uECC_MAX_WORDS != uECC_MIN_WORDS)
         "bx %[jump] \n\t"
     #endif
-        
+        "1: \n\t"
         "ldmia %[lptr]!, {%[left]} \n\t"
         "ldmia %[rptr]!, {%[right]} \n\t"
         "sbcs %[left], %[right] \n\t"