impl PUSHn

Author: lightsing

bus-mapping/src/evm/opcodes/pushn.rs

@@ -3,7 +3,7 @@ use crate::{
     circuit_input_builder::{CircuitInputStateRef, ExecStep},
     Error,
 };
-use eth_types::GethExecStep;
+use eth_types::{GethExecStep, Word};
 
 #[derive(Clone, Copy, Debug)]
 pub(crate) struct PushN;
@@ -16,27 +16,32 @@ impl Opcode for PushN {
         let geth_step = &geth_steps[0];
         let mut exec_step = state.new_step(geth_step)?;
 
-        let max_len = {
-            let code_hash = state.call()?.code_hash;
-            let code_size = state.code(code_hash)?.len();
-            let pc = geth_step.pc.0;
-            code_size - (pc + 1)
-        };
-
+        let code_hash = state.call()?.code_hash;
+        let code = state.code(code_hash)?;
+        let code_size = code.len();
+        let pc = geth_step.pc.0;
         let data_len = geth_step.op.data_len();
-
-        let real_value = geth_steps[1].stack.last()?;
-
-        let value = if data_len <= max_len {
-            real_value
+        let data_start = pc + 1;
+        let max_len = code_size - data_start;
+        let mut value_bytes = [0u8; 32];
+        if data_len <= max_len {
+            value_bytes[32 - data_len..].copy_from_slice(&code[data_start..data_start + data_len]);
         } else {
-            // If the bytecode is truncated, the bytecode circuit interprets only the actual data
-            // without zero-padding.
-            let missing_bits = (data_len - max_len) * 8;
-            real_value >> missing_bits
+            value_bytes[32 - max_len..].copy_from_slice(&code[data_start..]);
         };
-
-        state.stack_push(&mut exec_step, value)?;
+        let real_value = Word::from_big_endian(&value_bytes);
+        assert_eq!(real_value, geth_steps[1].stack.last()?);
+        let missing_bits = data_len.saturating_sub(max_len) * 8;
+
+        state.call_ctx_mut()?.stack.push(real_value)?;
+
+        // If the bytecode is truncated, the bytecode circuit interprets only the actual data
+        // without zero-padding.
+        state.stack_write(
+            &mut exec_step,
+            state.call_ctx()?.stack.last_filled(),
+            real_value >> missing_bits,
+        )?;
 
         Ok(vec![exec_step])
     }