From e963cff72de0efbd4e9c0b177caab88363f67d2e Mon Sep 17 00:00:00 2001
From: DavePutz <dwputz@gmail.com>
Date: Mon, 13 Jul 2020 22:27:06 -0500
Subject: [PATCH 1/4] Issue #2949 Run background checks during long
 multiplications

---
 py/mpz.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/py/mpz.c b/py/mpz.c
index 7800cdcc45a5f..8b8541c73785a 100644
--- a/py/mpz.c
+++ b/py/mpz.c
@@ -443,8 +443,11 @@ STATIC size_t mpn_mul(mpz_dig_t *idig, mpz_dig_t *jdig, size_t jlen, mpz_dig_t *
             *id++ = carry;
         }
 
-        ilen = id - oidig;
+      ilen = id - oidig;
+      // check to prevent usb starvation
+      RUN_BACKGROUND_TASKS;
     }
+    
 
     return ilen;
 }

From 30361f6f2a9cea4ae2aeb6dc41f5872d1f6fadee Mon Sep 17 00:00:00 2001
From: DavePutz <dwputz@gmail.com>
Date: Mon, 13 Jul 2020 22:39:30 -0500
Subject: [PATCH 2/4] Fix formatting

---
 py/mpz.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/py/mpz.c b/py/mpz.c
index 8b8541c73785a..05827d1045de3 100644
--- a/py/mpz.c
+++ b/py/mpz.c
@@ -443,12 +443,11 @@ STATIC size_t mpn_mul(mpz_dig_t *idig, mpz_dig_t *jdig, size_t jlen, mpz_dig_t *
             *id++ = carry;
         }
 
-      ilen = id - oidig;
-      // check to prevent usb starvation
-      RUN_BACKGROUND_TASKS;
+        ilen = id - oidig;
+        // check to prevent usb starvation
+        RUN_BACKGROUND_TASKS;
     }
     
-
     return ilen;
 }
 

From 14799f9ee6e634d73463a9ed401b5cc9a3219749 Mon Sep 17 00:00:00 2001
From: DavePutz <dwputz@gmail.com>
Date: Mon, 13 Jul 2020 22:43:46 -0500
Subject: [PATCH 3/4] more formatting fix

---
 py/mpz.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/py/mpz.c b/py/mpz.c
index 05827d1045de3..4ef00f73c9859 100644
--- a/py/mpz.c
+++ b/py/mpz.c
@@ -447,7 +447,7 @@ STATIC size_t mpn_mul(mpz_dig_t *idig, mpz_dig_t *jdig, size_t jlen, mpz_dig_t *
         // check to prevent usb starvation
         RUN_BACKGROUND_TASKS;
     }
-    
+
     return ilen;
 }
 

From e5f7adcf5d1257cefd33831d541b829ca8267aca Mon Sep 17 00:00:00 2001
From: DavePutz <dwputz@gmail.com>
Date: Mon, 13 Jul 2020 22:54:52 -0500
Subject: [PATCH 4/4] Fix to pass mpy-cross build

---
 py/mpz.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/py/mpz.c b/py/mpz.c
index 4ef00f73c9859..41b46f92ffc73 100644
--- a/py/mpz.c
+++ b/py/mpz.c
@@ -445,7 +445,9 @@ STATIC size_t mpn_mul(mpz_dig_t *idig, mpz_dig_t *jdig, size_t jlen, mpz_dig_t *
 
         ilen = id - oidig;
         // check to prevent usb starvation
+        #ifdef RUN_BACKGROUND_TASKS
         RUN_BACKGROUND_TASKS;
+        #endif
     }
 
     return ilen;