From 85411ac4755f17baf5e23a1e48d45f351626a272 Mon Sep 17 00:00:00 2001
From: Nicholas Ward <npward@berkeley.edu>
Date: Fri, 24 Feb 2023 13:59:13 -0800
Subject: [PATCH] fixes

---
 evm/src/cpu/kernel/asm/hash/sha2/compression.asm | 12 +++++-------
 evm/src/cpu/kernel/tests/hash.rs                 |  1 +
 2 files changed, 6 insertions(+), 7 deletions(-)

diff --git a/evm/src/cpu/kernel/asm/hash/sha2/compression.asm b/evm/src/cpu/kernel/asm/hash/sha2/compression.asm
index 800c2010..107d20b1 100644
--- a/evm/src/cpu/kernel/asm/hash/sha2/compression.asm
+++ b/evm/src/cpu/kernel/asm/hash/sha2/compression.asm
@@ -35,6 +35,8 @@ global sha2_compression:
     SWAP1
     // stack: num_blocks, scratch_space_addr, message_schedule_addr, i=0, a[0]..h[0], retdest
 compression_start_block:
+    // We keep the current values of the working variables saved at the end of the stack.
+    // These are the "initial values" to be added back in at the end of this block.
     // stack: num_blocks, scratch_space_addr, message_schedule_addr, i=0, a[0]..h[0], retdest
     %rep 8
         DUP12
@@ -183,17 +185,13 @@ compression_end_block:
     // stack: num_blocks, scratch_space_addr, message_schedule_addr, i, a[0]+a[64], b[0]+b[64], c[0]+c[64], d[0]+d[64], e[0]+e[64], f[0]+f[64], g[0]+g[64], h[0]+h[64], retdest
     %jump(compression_start_block)
 compression_end:
-    // stack: num_blocks, a[0]+a[64], b[0]+b[64], c[0]+c[64], d[0]+d[64], e[0]+e[64], f[0]+f[64], g[0]+g[64], h[0]+h[64], scratch_space_addr, message_schedule_addr, i, retdest
-    POP
-    // stack: a[0]+a[64], b[0]+b[64], c[0]+c[64], d[0]+d[64], e[0]+e[64], f[0]+f[64], g[0]+g[64], h[0]+h[64], scratch_space_addr, message_schedule_addr, i, retdest
+    // stack: num_blocks, scratch_space_addr, message_schedule_addr, i, a[0]+a[64], b[0]+b[64], c[0]+c[64], d[0]+d[64], e[0]+e[64], f[0]+f[64], g[0]+g[64], h[0]+h[64], retdest
+    %pop4
+    // stack: a[0]+a[64], b[0]+b[64], c[0]+c[64], d[0]+d[64], e[0]+e[64], f[0]+f[64], g[0]+g[64], h[0]+h[64], retdest
     %rep 7
         %shl_const(32)
         ADD // OR
     %endrep
-    // stack: concat(a[0]+a[64], b[0]+b[64], c[0]+c[64], d[0]+d[64], e[0]+e[64], f[0]+f[64], g[0]+g[64], h[0]+h[64]), scratch_space_addr, message_schedule_addr, i, retdest
-    SWAP3
-    // stack: i, scratch_space_addr, message_schedule_addr, concat(a[0]+a[64], b[0]+b[64], c[0]+c[64], d[0]+d[64], e[0]+e[64], f[0]+f[64], g[0]+g[64], h[0]+h[64]), retdest
-    %pop3
     // stack: sha2_result = concat(a[0]+a[64], b[0]+b[64], c[0]+c[64], d[0]+d[64], e[0]+e[64], f[0]+f[64], g[0]+g[64], h[0]+h[64]), retdest
     SWAP1
     JUMP
diff --git a/evm/src/cpu/kernel/tests/hash.rs b/evm/src/cpu/kernel/tests/hash.rs
index bc73ecd5..432fcf39 100644
--- a/evm/src/cpu/kernel/tests/hash.rs
+++ b/evm/src/cpu/kernel/tests/hash.rs
@@ -90,6 +90,7 @@ fn test_hash_256(
     let (expected, result_stack) =
         prepare_test(hash_fn_label, hash_input_virt, standard_implementation).unwrap();
 
+
     // Extract the final output.
     let actual = result_stack[0];