xwing integration: add new functions to x25519 to facilitate xwing in…

…tregration

src/crypto_scalarmult/curve25519/amd64/ref4/curve25519.jinc

@@ -155,6 +155,22 @@ inline fn __curve25519_ref4(reg u64[4] _k _u) -> reg u64[4]
   return r;
 }
 
+inline fn __curve25519_ref4_ptr(#spill_to_mmx reg u64 rp, reg u64 kp up)
+{
+  reg u64[4] r k u;
+
+  ()  = #spill(rp);
+
+  k = __load4(kp);
+  u = __load4(up);
+  r = __curve25519_ref4(k, u);
+
+  ()  = #unspill(rp);
+
+  __store4(rp, r);
+}
+
+
 inline fn __curve25519_ref4_base(reg u64[4] _k) -> reg u64[4]
 {
   stack u8[32] k;
@@ -167,3 +183,18 @@ inline fn __curve25519_ref4_base(reg u64[4] _k) -> reg u64[4]
   return r;
 }
 
+inline fn __curve25519_ref4_base_ptr(#spill_to_mmx reg u64 rp, reg u64 kp)
+{
+  reg u64[4] r k;
+
+  () = #spill(rp);
+
+  k = __load4(kp);
+  r = __curve25519_ref4_base(k);
+
+  ()  = #unspill(rp);
+
+  __store4(rp, r);
+}
+
+

src/crypto_scalarmult/curve25519/amd64/ref4/scalarmult.jazz

@@ -4,18 +4,10 @@ require "curve25519.jinc"
 export fn jade_scalarmult_curve25519_amd64_ref4(#spill_to_mmx reg u64 qp np pp) -> reg u64
 {
   reg u64 r;
-  reg u64[4] q n p;
 
   _ = #init_msf();
 
-  ()  = #spill(qp);
-  n   = __load4(np);
-  p   = __load4(pp);
-
-  q = __curve25519_ref4(n, p);
-
-  ()  = #unspill(qp);
-  __store4(qp, q);
+  __curve25519_ref4_ptr(qp, np, pp);
 
   ?{}, r = #set0();
   return r;
@@ -24,17 +16,10 @@ export fn jade_scalarmult_curve25519_amd64_ref4(#spill_to_mmx reg u64 qp np pp)
 export fn jade_scalarmult_curve25519_amd64_ref4_base(#spill_to_mmx reg u64 qp np) -> reg u64
 {
   reg u64 r;
-  reg u64[4] q n;
 
   _ = #init_msf();
 
-  ()  = #spill(qp);
-  n   = __load4(np);
-
-  q = __curve25519_ref4_base(n);
-
-  ()  = #unspill(qp);
-  __store4(qp, q);
+  __curve25519_ref4_base_ptr(qp, np);
 
   ?{}, r = #set0();
   return r;