From: Chris Duncan <chris@zoso.dev>
Date: Fri, 2 Oct 2026 09:43:29 +0000 (-0700)
Subject: Move final field element scratch buffer.
X-Git-Url: https://git.codecow.com/?a=commitdiff_plain;h=588703317d43c627bd51922db636514595325195;p=nano25519.git

Move final field element scratch buffer.
---

diff --git a/src/assembly/ed25519/fe.ts b/src/assembly/ed25519/fe.ts
index 632ef5c..ec0660e 100644
--- a/src/assembly/ed25519/fe.ts
+++ b/src/assembly/ed25519/fe.ts
@@ -178,14 +178,14 @@ export function fe_frombytes (h: FieldElement, s: StaticArray<u8>): void {
 	store<i32>(h_ptr, h9, 36)
 }
 
-const t0: FieldElement = fe()
-const t1: FieldElement = fe()
-const t2: FieldElement = fe()
-const t3: FieldElement = fe()
 /**
  * Inversion - sets `out` = 0 if `z` == 0
  */
-export function fe_invert (out: FieldElement, z: FieldElement): void {
+export function fe_invert (out: FieldElement, z: FieldElement, fe_scratch_0: FieldElement, fe_scratch_1: FieldElement, fe_scratch_2: FieldElement, fe_scratch_3: FieldElement): void {
+	const t0: FieldElement = fe_scratch_0
+	const t1: FieldElement = fe_scratch_1
+	const t2: FieldElement = fe_scratch_2
+	const t3: FieldElement = fe_scratch_3
 	fe_sq(t0, z)
 	fe_sq(t1, t0)
 	fe_sq(t1, t1)
@@ -505,9 +505,6 @@ export function fe_neg (h: FieldElement, f: FieldElement): void {
 	v128.store_lane<i64>(h_ptr, v128.neg<i32>(v128.load(f_ptr, 32)), 0, 32)
 }
 
-const fe_pow22523_t0: FieldElement = fe()
-const fe_pow22523_t1: FieldElement = fe()
-const fe_pow22523_t2: FieldElement = fe()
 /**
  * returns z^((p-5)/8) = z^(2²⁵²-3)
  * used to compute square roots since we have p=5 (mod 8); see Cohen and Frey.
diff --git a/src/assembly/ed25519/p.ts b/src/assembly/ed25519/p.ts
index 6874727..fe5a952 100644
--- a/src/assembly/ed25519/p.ts
+++ b/src/assembly/ed25519/p.ts
@@ -105,20 +105,26 @@ export function ge_p3_to_cached (r: ge_cached, p: ge_p3): void {
 	fe_mul(r.T2d, p.T, ed25519_d2)
 }
 
-const ge_p3_tobytes_fe_scratch: FieldElement = fe()
+const ge_p3_tobytes_fe_scratch_0: FieldElement = fe()
+const ge_p3_tobytes_fe_scratch_1: FieldElement = fe()
+const ge_p3_tobytes_fe_scratch_2: FieldElement = fe()
+const ge_p3_tobytes_fe_scratch_3: FieldElement = fe()
 const ge_p3_tobytes_recip: FieldElement = fe()
 const ge_p3_tobytes_x: FieldElement = fe()
 const ge_p3_tobytes_y: FieldElement = fe()
 export function ge_p3_tobytes (s: StaticArray<u8>, h: ge_p3): void {
-	const fe_scratch = ge_p3_tobytes_fe_scratch
+	const fe_scratch_0 = ge_p3_tobytes_fe_scratch_0
+	const fe_scratch_1 = ge_p3_tobytes_fe_scratch_1
+	const fe_scratch_2 = ge_p3_tobytes_fe_scratch_2
+	const fe_scratch_3 = ge_p3_tobytes_fe_scratch_3
 	const recip = ge_p3_tobytes_recip
 	const x = ge_p3_tobytes_x
 	const y = ge_p3_tobytes_y
-	fe_invert(recip, h.Z)
+	fe_invert(recip, h.Z, fe_scratch_0, fe_scratch_1, fe_scratch_2, fe_scratch_3)
 	fe_mul(x, h.X, recip)
 	fe_mul(y, h.Y, recip)
-	fe_tobytes(s, y, fe_scratch)
-	s[31] ^= fe_isnegative(x, fe_scratch) << 7
+	fe_tobytes(s, y, fe_scratch_0)
+	s[31] ^= fe_isnegative(x, fe_scratch_0) << 7
 }
 
 const ge_p2_dbl_t: FieldElement = fe()