From d185d30e8961b1f43e04276b56f3738d40d39811 Mon Sep 17 00:00:00 2001
From: Robin Salen <salenrobin@gmail.com>
Date: Mon, 23 Oct 2023 07:55:09 -0400
Subject: [PATCH 1/2] Speed-up memset and fix it to write 0 values

---
 evm/src/cpu/kernel/asm/account_code.asm    |  2 +-
 evm/src/cpu/kernel/asm/bignum/util.asm     |  2 +-
 evm/src/cpu/kernel/asm/memory/memset.asm   | 47 +++++++++++++---------
 evm/src/cpu/kernel/asm/memory/syscalls.asm |  2 +-
 4 files changed, 31 insertions(+), 22 deletions(-)

diff --git a/evm/src/cpu/kernel/asm/account_code.asm b/evm/src/cpu/kernel/asm/account_code.asm
index d7d09b5b7e..35f9c62dd1 100644
--- a/evm/src/cpu/kernel/asm/account_code.asm
+++ b/evm/src/cpu/kernel/asm/account_code.asm
@@ -190,7 +190,7 @@ extcodecopy_large_offset:
     // offset is larger than the code size. So we just have to write zeros.
     // stack: code_size, size, offset, dest_offset, retdest
     GET_CONTEXT
-    %stack (context, code_size, size, offset, dest_offset, retdest) -> (context, @SEGMENT_MAIN_MEMORY, dest_offset, 0, size, retdest)
+    %stack (context, code_size, size, offset, dest_offset, retdest) -> (context, @SEGMENT_MAIN_MEMORY, dest_offset, size, retdest)
     %jump(memset)
 
 // Loads the code at `address` into memory, at the given context and segment, starting at offset 0.
diff --git a/evm/src/cpu/kernel/asm/bignum/util.asm b/evm/src/cpu/kernel/asm/bignum/util.asm
index 79cbc1ec5e..7bd6e0dc33 100644
--- a/evm/src/cpu/kernel/asm/bignum/util.asm
+++ b/evm/src/cpu/kernel/asm/bignum/util.asm
@@ -9,7 +9,7 @@
 %macro clear_current_general
     // stack: dst, len
     GET_CONTEXT
-    %stack (context, dst, len) -> (context, @SEGMENT_KERNEL_GENERAL, dst, 0, len, %%after)
+    %stack (context, dst, len) -> (context, @SEGMENT_KERNEL_GENERAL, dst, len, %%after)
     %jump(memset)
 %%after:
 %endmacro
diff --git a/evm/src/cpu/kernel/asm/memory/memset.asm b/evm/src/cpu/kernel/asm/memory/memset.asm
index 77b37f6413..b04ade220b 100644
--- a/evm/src/cpu/kernel/asm/memory/memset.asm
+++ b/evm/src/cpu/kernel/asm/memory/memset.asm
@@ -1,38 +1,47 @@
-// Sets `count` values to `value` at
+// Sets `count` values to 0 at
 //     DST = (dst_ctx, dst_segment, dst_addr).
 // This tuple definition is used for brevity in the stack comments below.
 global memset:
-    // stack: DST, value, count, retdest
-    DUP5
-    // stack: count, DST, value, count, retdest
-    ISZERO
-    // stack: count == 0, DST, value, count, retdest
+    // stack: DST, count, retdest
+    DUP4
+    // stack: count, DST, count, retdest
+    %lt_const(0x20)
+    // stack: count < 32, DST, count, retdest
     %jumpi(memset_finish)
-    // stack: DST, value, count, retdest
+    // stack: DST, count, retdest
     
-    DUP4
-    // stack: value, DST, value, count, retdest
-    DUP4
-    DUP4
-    DUP4
-    // stack: DST, value, DST, value, count, retdest
-    MSTORE_GENERAL
-    // stack: DST, value, count, retdest
+    // stack: DST, count, retdest
+    PUSH 32
+    PUSH 0
+    DUP5
+    DUP5
+    DUP5
+    // stack: DST, 0, 32, DST, count, retdest
+    MSTORE_32BYTES
+    // stack: DST, count, retdest
 
     // Increment dst_addr.
     SWAP2
-    %increment
+    %add_const(0x20)
     SWAP2
     // Decrement count.
     SWAP4
-    %decrement
+    %sub_const(0x20)
     SWAP4
 
     // Continue the loop.
     %jump(memset)
 
 memset_finish:
-    // stack: DST, value, count, retdest
-    %pop5
+    // stack: DST, final_count, retdest
+    DUP4
+    PUSH 0
+    DUP5
+    DUP5
+    DUP5
+    // stack: DST, 0, final_count, DST, final_count, retdest
+    MSTORE_32BYTES
+    // stack: DST, final_count, retdest
+    %pop4
     // stack: retdest
     JUMP
diff --git a/evm/src/cpu/kernel/asm/memory/syscalls.asm b/evm/src/cpu/kernel/asm/memory/syscalls.asm
index f23d261105..20f584f7cf 100644
--- a/evm/src/cpu/kernel/asm/memory/syscalls.asm
+++ b/evm/src/cpu/kernel/asm/memory/syscalls.asm
@@ -109,7 +109,7 @@ wcopy_large_offset:
     // stack: kexit_info, dest_offset, offset, size
     GET_CONTEXT
     %stack (context, kexit_info, dest_offset, offset, size) ->
-        (context, @SEGMENT_MAIN_MEMORY, dest_offset, 0, size, wcopy_after, kexit_info)
+        (context, @SEGMENT_MAIN_MEMORY, dest_offset, size, wcopy_after, kexit_info)
     %jump(memset)
 
 wcopy_after:

From 385ab3c64f0ee73e7447c89e55086393520bbefb Mon Sep 17 00:00:00 2001
From: Robin Salen <salenrobin@gmail.com>
Date: Mon, 23 Oct 2023 08:15:10 -0400
Subject: [PATCH 2/2] Remove redundant

---
 evm/src/cpu/kernel/asm/memory/memset.asm | 2 --
 1 file changed, 2 deletions(-)

diff --git a/evm/src/cpu/kernel/asm/memory/memset.asm b/evm/src/cpu/kernel/asm/memory/memset.asm
index b04ade220b..c0bad482fa 100644
--- a/evm/src/cpu/kernel/asm/memory/memset.asm
+++ b/evm/src/cpu/kernel/asm/memory/memset.asm
@@ -8,8 +8,6 @@ global memset:
     %lt_const(0x20)
     // stack: count < 32, DST, count, retdest
     %jumpi(memset_finish)
-    // stack: DST, count, retdest
-    
     // stack: DST, count, retdest
     PUSH 32
     PUSH 0