> For the complete documentation index, see [llms.txt](https://validium.gitbook.io/docs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://validium.gitbook.io/docs/components/compiler/specification/instructions/evm/environment.md).
# Environment
***
### ADDRESS
Original [EVM](https://www.evm.codes/#30?fork=shanghai) instruction.
This value is fetched with a native [EraVM instruction: `context.this`](https://matter-labs.github.io/eravm-spec/spec.html#ContextDefinitions).
#### LLVM IR
[The LLVM IR generator code](https://github.com/matter-labs/era-compiler-solidity/blob/main/src/yul/parser/statement/expression/function_call/mod.rs#L973) is common for Yul and EVMLA representations.
### BALANCE
Original [EVM](https://www.evm.codes/#31?fork=shanghai) instruction.
#### System Contract
This information is requested a System Contract called [L2BaseToken](https://github.com/code-423n4/2024-03-zksync/blob/main/code/system-contracts/contracts/L2BaseToken.sol).
On how the System Contract is called, see [this section](https://docs.zksync.io/zk-stack/components/compiler/specification/system-contracts#environmental-data-storage).
#### LLVM IR
[The LLVM IR generator code](https://github.com/matter-labs/era-compiler-llvm-context/blob/main/src/eravm/evm/ether_gas.rs#L39) is common for Yul and EVMLA representations.
The request to the System Contract is done via the [SystemRequest](https://github.com/matter-labs/era-compiler-llvm-context/blob/main/src/eravm/context/function/runtime/system_request.rs) runtime function.
### ORIGIN
Original [EVM](https://www.evm.codes/#32?fork=shanghai) instruction.
#### System Contract
This information is requested a System Contract called [SystemContext](https://github.com/matter-labs/era-system-contracts/blob/main/contracts/SystemContext.sol).
On how the System Contract is called, see [this section](https://docs.zksync.io/zk-stack/components/compiler/specification/system-contracts#environmental-data-storage).
#### LLVM IR
[The LLVM IR generator code](https://github.com/matter-labs/era-compiler-llvm-context/blob/main/src/eravm/evm/context.rs#L47) is common for Yul and EVMLA representations.
The request to the System Contract is done via the [SystemRequest](https://github.com/matter-labs/era-compiler-llvm-context/blob/main/src/eravm/context/function/runtime/system_request.rs) runtime function.
### CALLER
Original [EVM](https://www.evm.codes/#33?fork=shanghai) instruction.
This value is fetched with a native [EraVM instruction: `context.caller`](https://matter-labs.github.io/eravm-spec/spec.html#ContextDefinitions).
#### LLVM IR
[The LLVM IR generator code](https://github.com/matter-labs/era-compiler-solidity/blob/main/src/yul/parser/statement/expression/function_call/mod.rs#L974) is common for Yul and EVMLA representations.
### CALLVALUE
Original [EVM](https://www.evm.codes/#34?fork=shanghai) instruction.
This value is fetched with a native [EraVM instruction: `context.get_context_u128`](https://matter-labs.github.io/eravm-spec/spec.html#ContextDefinitions).
#### LLVM IR
[The LLVM IR generator code](https://github.com/matter-labs/era-compiler-llvm-context/blob/main/src/eravm/evm/ether_gas.rs#L25) is common for Yul and EVMLA representations.
### CALLDATALOAD
Original [EVM](https://www.evm.codes/#35?fork=shanghai) instruction.
Calldata is accessed with a generic memory access instruction, but the memory chunk itself is a reference to the calling contract's heap. A fat pointer to the parent contract is passed via ABI using registers.
Then, the pointer [is saved to a global stack variable](https://github.com/matter-labs/era-compiler-llvm-context/blob/main/src/eravm/context/function/runtime/entry.rs#L129) accessible from anywhere in the contract.
#### LLVM IR
```llvm
@ptr_calldata = private unnamed_addr global ptr addrspace(3) null ; global variable declaration
...
store ptr addrspace(3) %0, ptr @ptr_calldata, align 32 ; saving the pointer from `r1` to the global variable
...
%calldata_pointer = load ptr addrspace(3), ptr @ptr_calldata, align 32 ; loading the pointer from the global variable to `calldata_pointer`
%calldata_value = load i256, ptr addrspace(3) %calldata_pointer, align 32 ; loading the value from the calldata pointer
```
[The LLVM IR generator code](https://github.com/matter-labs/era-compiler-llvm-context/blob/main/src/eravm/evm/calldata.rs#L14) is common for Yul and EVMLA representations.
#### EraVM Assembly
```llvm
ptr.add r1, r0, stack[@ptr_calldata] ; saving the pointer from `r1` to the global variable
...
ptr.add stack[@ptr_calldata], r0, r1 ; loading the pointer from the global variable to `r1`
ld r1, r1 ; loading the value to `r1`
```
* [EraVM instruction: `ptr.add`](https://matter-labs.github.io/eravm-spec/spec.html#PtrAddDefinition)
* [EraVM fat pointers](https://matter-labs.github.io/eravm-spec/spec.html#PointerDefinitions)
* [EraVM memory forwarding mechanism](https://matter-labs.github.io/eravm-spec/spec.html#MemoryForwarding)
### CALLDATASIZE
Original [EVM](https://www.evm.codes/#36?fork=shanghai) instruction.
Calldata size is stored in the fat pointer passed from the parent contract (see [CALLDATALOAD](https://docs.zksync.io/zk-stack/components/compiler/specification/instructions/evm/environment#calldataload)).
The size value can be extracted with bitwise operations as illustrated below.
#### LLVM IR
```llvm
@calldatasize = private unnamed_addr global i256 0 ; global variable declaration
...
%abi_pointer_value = ptrtoint ptr addrspace(3) %0 to i256 ; converting the pointer to an integer
%abi_pointer_value_shifted = lshr i256 %abi_pointer_value, 96 ; shifting the integer right 96 bits
%abi_length_value = and i256 %abi_pointer_value_shifted, 4294967295 ; keeping the lowest 32 bits of the integer
store i256 %abi_length_value, ptr @calldatasize, align 32 ; saving the value to the global variable
```
[The LLVM IR generator code](https://github.com/matter-labs/era-compiler-llvm-context/blob/main/src/eravm/evm/calldata.rs#L40) is common for Yul and EVMLA representations.
#### EraVM Assembly
```llvm
ptr.add r1, r0, stack[@ptr_calldata] ; saving the pointer from `r1` to the global variable
shr.s 96, r1, r1 ; shifting the integer right 96 bits
and @CPI0_0[0], r1, stack[@calldatasize] ; keeping the lowest 32 bits of the integer, saving the value to the global variable
...
CPI0_0:
.cell 4294967295
```
* [EraVM instruction: `ptr.add`](https://matter-labs.github.io/eravm-spec/spec.html#PtrAddDefinition)
* [EraVM fat pointers](https://matter-labs.github.io/eravm-spec/spec.html#PointerDefinitions)
* [EraVM memory forwarding mechanism](https://matter-labs.github.io/eravm-spec/spec.html#MemoryForwarding)
### CALLDATACOPY
Original [EVM](https://www.evm.codes/#37?fork=shanghai) instruction.
Unlike on EVM, on EraVM it is a simple loop over [CALLDATALOAD](https://docs.zksync.io/zk-stack/components/compiler/specification/instructions/evm/environment#calldataload)).
#### LLVM IR
```llvm
; loading the pointer from the global variable to `calldata_pointer`
%calldata_pointer = load ptr addrspace(3), ptr @ptr_calldata, align 32
; shifting the pointer by 122 bytes
%calldata_source_pointer = getelementptr i8, ptr addrspace(3) %calldata_pointer, i256 122
; copying 64 bytes from calldata at offset 122 to the heap at offset 128
call void @llvm.memcpy.p1.p3.i256(ptr addrspace(1) align 1 inttoptr (i256 128 to ptr addrspace(1)), ptr addrspace(3) align 1 %calldata_source_pointer, i256 64, i1 false)
```
[The LLVM IR generator code](https://github.com/matter-labs/era-compiler-llvm-context/blob/main/src/eravm/evm/calldata.rs#L54) is common for Yul and EVMLA representations.
#### EraVM Assembly
```
.BB0_3:
shl.s 5, r2, r3 ; shifting the offset by 32
ptr.add r1, r3, r4 ; adding the offset to the calldata pointer
ld r4, r4 ; reading the calldata value
add 128, r3, r3 ; adding the offset to the heap pointer
st.1 r3, r4 ; writing the calldata value to the heap
add 1, r2, r2 ; incrementing the offset
sub.s! 2, r2, r3 ; checking the bounds
jump.lt @.BB0_3 ; loop continuation branching
```
* [EraVM instruction: `ptr.add`](https://matter-labs.github.io/eravm-spec/spec.html#PtrAddDefinition)
* [EraVM fat pointers](https://matter-labs.github.io/eravm-spec/spec.html#PointerDefinitions)
* [EraVM memory forwarding mechanism](https://matter-labs.github.io/eravm-spec/spec.html#MemoryForwarding)
### CODECOPY
Original [EVM](https://www.evm.codes/#38?fork=shanghai) instruction.
See [the EraVM docs](https://docs.zksync.io/build/developer-reference/ethereum-differences/evm-instructions#codecopy).
[The LLVM IR generator code](https://github.com/matter-labs/era-compiler-solidity/blob/main/src/evmla/ethereal_ir/function/block/element/mod.rs#L856).
### CODESIZE
Original [EVM](https://www.evm.codes/#39?fork=shanghai) instruction.
See [the EraVM docs](https://docs.zksync.io/build/developer-reference/ethereum-differences/evm-instructions#codesize).
[The LLVM IR generator code](https://github.com/matter-labs/era-compiler-solidity/blob/main/src/evmla/ethereal_ir/function/block/element/mod.rs#L837).
### GASPRICE
Original [EVM](https://www.evm.codes/#3a?fork=shanghai) instruction.
#### System Contract
This information is requested a System Contract called [SystemContext](https://github.com/matter-labs/era-system-contracts/blob/main/contracts/SystemContext.sol).
On how the System Contract is called, see [this section](https://docs.zksync.io/zk-stack/components/compiler/specification/system-contracts#environmental-data-storage).
#### LLVM IR
[The LLVM IR generator code](https://github.com/matter-labs/era-compiler-llvm-context/blob/main/src/eravm/evm/context.rs#L30) is common for Yul and EVMLA representations.
The request to the System Contract is done via the [SystemRequest](https://github.com/matter-labs/era-compiler-llvm-context/blob/main/src/eravm/context/function/runtime/system_request.rs) runtime function.
### EXTCODESIZE
Original [EVM](https://www.evm.codes/#3b?fork=shanghai) instruction.
#### System Contract
This information is requested a System Contract called [AccountCodeStorage](https://github.com/matter-labs/era-system-contracts/blob/main/contracts/AccountCodeStorage.sol).
On how the System Contract is called, see [this section](https://docs.zksync.io/zk-stack/components/compiler/specification/system-contracts#environmental-data-storage).
#### LLVM IR
[The LLVM IR generator code](https://github.com/matter-labs/era-compiler-llvm-context/blob/main/src/eravm/evm/ext_code.rs#L11) is common for Yul and EVMLA representations.
The request to the System Contract is done via the [SystemRequest](https://github.com/matter-labs/era-compiler-llvm-context/blob/main/src/eravm/context/function/runtime/system_request.rs) runtime function.
### EXTCODECOPY
Original [EVM](https://www.evm.codes/#3c?fork=shanghai) instruction.
Not supported. Triggers a compile-time error.
### RETURNDATASIZE
Original [EVM](https://www.evm.codes/#3d?fork=shanghai) instruction.
Return data size is read from the fat pointer returned from the child contract.
The size value can be extracted with bitwise operations as illustrated below.
#### LLVM IR
```llvm
%contract_call_external = tail call { ptr addrspace(3), i1 } @__farcall(i256 0, i256 0, i256 undef, i256 undef, i256 undef, i256 undef, i256 undef, i256 undef, i256 undef, i256 undef, i256 undef, i256 undef)
%contract_call_external_result_abi_data = extractvalue { ptr addrspace(3), i1 } %contract_call_external, 0
%contract_call_memcpy_from_child_pointer_casted = ptrtoint ptr addrspace(3) %contract_call_external_result_abi_data to i256
%contract_call_memcpy_from_child_return_data_size_shifted = lshr i256 %contract_call_memcpy_from_child_pointer_casted, 96
%contract_call_memcpy_from_child_return_data_size_truncated = and i256 %contract_call_memcpy_from_child_return_data_size_shifted, 4294967295
```
[The LLVM IR generator code](https://github.com/matter-labs/era-compiler-llvm-context/blob/main/src/eravm/evm/return_data.rs#L16) is common for Yul and EVMLA representations.
#### EraVM Assembly
```llvm
near_call r0, @__farcall, @DEFAULT_UNWIND ; calling a child contract
shr.s 96, r1, r1 ; shifting the pointer value right 96 bits
and @CPI0_1[0], r1, r1 ; keeping the lowest 32 bits of the pointer value
...
CPI0_1:
.cell 4294967295
```
[EraVM instruction: `call`](https://matter-labs.github.io/eravm-spec/spec.html#NearCallDefinition)
### RETURNDATACOPY
Original [EVM](https://www.evm.codes/#3e?fork=shanghai) instruction.
Unlike on EVM, on EraVM it is a simple loop over memory operations on 256-bit values.
#### LLVM IR
```llvm
; loading the pointer from the global variable to `return_data_pointer`
%return_data_pointer = load ptr addrspace(3), ptr @ptr_return_data, align 32
; shifting the pointer by 122 bytes
%return_data_source_pointer = getelementptr i8, ptr addrspace(3) %return_data_pointer, i256 122
; copying 64 bytes from return data at offset 122 to the heap at offset 128
call void @llvm.memcpy.p1.p3.i256(ptr addrspace(1) align 1 inttoptr (i256 128 to ptr addrspace(1)), ptr addrspace(3) align 1 %return_data_source_pointer, i256 64, i1 false)
```
[The LLVM IR generator code](https://github.com/matter-labs/era-compiler-llvm-context/blob/main/src/eravm/evm/return_data.rs#L31) is common for Yul and EVMLA representations.
#### EraVM Assembly
```llvm
.BB0_3:
shl.s 5, r2, r3 ; shifting the offset by 32
ptr.add r1, r3, r4 ; adding the offset to the return data pointer
ld r4, r4 ; reading the return data value
add 128, r3, r3 ; adding the offset to the heap pointer
st.1 r3, r4 ; writing the return data value to the heap
add 1, r2, r2 ; incrementing the offset
sub.s! 2, r2, r3 ; checking the bounds
jump.lt @.BB0_3 ; loop continuation branching
```
* [EraVM instruction: `jump`](https://matter-labs.github.io/eravm-spec/spec.html#JumpDefinition)
* [EraVM instruction predication](https://matter-labs.github.io/eravm-spec/spec.html#Predication)
### EXTCODEHASH
Original [EVM](https://www.evm.codes/#3f?fork=shanghai) instruction.
#### System Contract
This information is requested a System Contract called [AccountCodeStorage](https://github.com/matter-labs/era-system-contracts/blob/main/contracts/AccountCodeStorage.sol).
On how the System Contract is called, see [this section](https://docs.zksync.io/zk-stack/components/compiler/specification/system-contracts#environmental-data-storage).
#### LLVM IR
[The LLVM IR generator code](https://github.com/matter-labs/era-compiler-llvm-context/blob/main/src/eravm/evm/ext_code.rs#L29) is common for Yul and EVMLA representations.
The request to the System Contract is done via the [SystemRequest](https://github.com/matter-labs/era-compiler-llvm-context/blob/main/src/eravm/context/function/runtime/system_request.rs) runtime function.