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use vm_core::{Felt, ZERO};
use super::FastProcessor;
use crate::{ErrorContext, ExecutionError, utils::split_element};
impl FastProcessor {
/// Analogous to `Process::op_u32split`.
pub fn op_u32split(&mut self) -> Result<(), ExecutionError> {
let top = self.stack_get(0);
let (hi, lo) = split_element(top);
self.increment_stack_size();
self.stack_write(0, hi);
self.stack_write(1, lo);
Ok(())
}
/// Analogous to `Process::op_u32add`.
pub fn op_u32add(&mut self) -> Result<(), ExecutionError> {
self.u32_pop2_applyfn_push_lowhigh(|a, b| a + b)
}
/// Analogous to `Process::op_u32add3`.
///
/// Pops three elements off the stack, adds them, splits the result into low and high 32-bit
/// values, and pushes these values back onto the stack.
///
/// The size of the stack is decremented by 1.
pub fn op_u32add3(&mut self) -> Result<(), ExecutionError> {
let (sum_hi, sum_lo) = {
let c = self.stack_get(0).as_int();
let b = self.stack_get(1).as_int();
let a = self.stack_get(2).as_int();
// Check that a, b, and c are u32 values.
if a > u32::MAX as u64 {
return Err(ExecutionError::not_u32_value(
Felt::new(a),
ZERO,
&ErrorContext::default(),
));
}
if b > u32::MAX as u64 {
return Err(ExecutionError::not_u32_value(
Felt::new(b),
ZERO,
&ErrorContext::default(),
));
}
if c > u32::MAX as u64 {
return Err(ExecutionError::not_u32_value(
Felt::new(c),
ZERO,
&ErrorContext::default(),
));
}
let result = Felt::new(a + b + c);
split_element(result)
};
// write the high 32 bits to the new top of the stack, and low 32 bits after
self.decrement_stack_size();
self.stack_write(0, sum_hi);
self.stack_write(1, sum_lo);
Ok(())
}
/// Analogous to `Process::op_u32sub`.
pub fn op_u32sub(&mut self, op_idx: usize) -> Result<(), ExecutionError> {
let op_idx = Felt::from(op_idx as u32);
self.u32_pop2_applyfn_push_results(op_idx, |first_old, second_old| {
let result = second_old.wrapping_sub(first_old);
let first_new = result >> 63;
let second_new = result & u32::MAX as u64;
Ok((first_new, second_new))
})
}
/// Analogous to `Process::op_u32mul`.
pub fn op_u32mul(&mut self) -> Result<(), ExecutionError> {
self.u32_pop2_applyfn_push_lowhigh(|a, b| a * b)
}
/// Analogous to `Process::op_u32madd`.
///
/// Pops three elements off the stack, multiplies the first two and adds the third element to
/// the result, splits the result into low and high 32-bit values, and pushes these values
/// back onto the stack.
pub fn op_u32madd(&mut self) -> Result<(), ExecutionError> {
let (result_hi, result_lo) = {
let b = self.stack_get(0).as_int();
let a = self.stack_get(1).as_int();
let c = self.stack_get(2).as_int();
// Check that a, b, and c are u32 values.
if b > u32::MAX as u64 {
return Err(ExecutionError::not_u32_value(
Felt::new(a),
ZERO,
&ErrorContext::default(),
));
}
if a > u32::MAX as u64 {
return Err(ExecutionError::not_u32_value(
Felt::new(b),
ZERO,
&ErrorContext::default(),
));
}
if c > u32::MAX as u64 {
return Err(ExecutionError::not_u32_value(
Felt::new(c),
ZERO,
&ErrorContext::default(),
));
}
let result = Felt::new(a * b + c);
split_element(result)
};
// write the high 32 bits to the new top of the stack, and low 32 bits after
self.decrement_stack_size();
self.stack_write(0, result_hi);
self.stack_write(1, result_lo);
Ok(())
}
/// Analogous to `Process::op_u32div`.
pub fn op_u32div(&mut self, op_idx: usize) -> Result<(), ExecutionError> {
let clk = self.clk + op_idx;
self.u32_pop2_applyfn_push_results(ZERO, |first, second| {
if first == 0 {
return Err(ExecutionError::divide_by_zero(clk, &ErrorContext::default()));
}
// a/b = n*q + r for some n>=0 and 0<=r<b
let q = second / first;
let r = second - q * first;
// r is placed on top of the stack, followed by q
Ok((r, q))
})
}
/// Analogous to `Process::op_u32and`.
pub fn op_u32and(&mut self) -> Result<(), ExecutionError> {
self.u32_pop2_applyfn_push(|a, b| a & b)
}
/// Analogous to `Process::op_u32xor`.
pub fn op_u32xor(&mut self) -> Result<(), ExecutionError> {
self.u32_pop2_applyfn_push(|a, b| a ^ b)
}
/// Analogous to `Process::op_u32assert2`.
pub fn op_u32assert2(&mut self, err_code: Felt) -> Result<(), ExecutionError> {
self.u32_pop2_applyfn_push_results(err_code, |first, second| Ok((first, second)))
}
// HELPERS
// ----------------------------------------------------------------------------------------------
/// Equivalent to `pop2_applyfn_push`, but for u32 values.
fn u32_pop2_applyfn_push(
&mut self,
f: impl FnOnce(u64, u64) -> u64,
) -> Result<(), ExecutionError> {
let b = self.stack_get(0).as_int();
let a = self.stack_get(1).as_int();
// Check that a and b are u32 values.
if b > u32::MAX as u64 {
return Err(ExecutionError::not_u32_value(
Felt::new(b),
ZERO,
&ErrorContext::default(),
));
}
if a > u32::MAX as u64 {
return Err(ExecutionError::not_u32_value(
Felt::new(a),
ZERO,
&ErrorContext::default(),
));
}
let result = f(a, b);
self.decrement_stack_size();
self.stack_write(0, Felt::new(result));
Ok(())
}
/// Pops 2 elements from the stack, applies the given function to them, and pushes the low/high
/// u32 values of the result back onto the stack.
///
/// Specifically, this function
/// 1. pops the top two elements from the stack,
/// 2. applies the given function to them,
/// 3. splits the result into low/high u32 values, and
/// 4. pushes the low/high values back onto the stack.
///
/// The size of the stack doesn't change.
#[inline(always)]
fn u32_pop2_applyfn_push_lowhigh(
&mut self,
f: impl FnOnce(u64, u64) -> u64,
) -> Result<(), ExecutionError> {
let b = self.stack_get(0).as_int();
let a = self.stack_get(1).as_int();
// Check that a and b are u32 values.
if a > u32::MAX as u64 {
return Err(ExecutionError::not_u32_value(
Felt::new(a),
ZERO,
&ErrorContext::default(),
));
}
if b > u32::MAX as u64 {
return Err(ExecutionError::not_u32_value(
Felt::new(b),
ZERO,
&ErrorContext::default(),
));
}
let result = Felt::new(f(a, b));
let (hi, lo) = split_element(result);
self.stack_write(0, hi);
self.stack_write(1, lo);
Ok(())
}
/// Pops 2 elements from the stack, applies the given function to them, and pushes the resulting
/// 2 u32 values back onto the stack.
///
/// The size of the stack doesn't change.
#[inline(always)]
fn u32_pop2_applyfn_push_results(
&mut self,
err_code: Felt,
f: impl FnOnce(u64, u64) -> Result<(u64, u64), ExecutionError>,
) -> Result<(), ExecutionError> {
let first_old = self.stack_get(0).as_int();
let second_old = self.stack_get(1).as_int();
// Check that a and b are u32 values.
if first_old > u32::MAX as u64 {
return Err(ExecutionError::not_u32_value(
Felt::new(first_old),
err_code,
&ErrorContext::default(),
));
}
if second_old > u32::MAX as u64 {
return Err(ExecutionError::not_u32_value(
Felt::new(second_old),
err_code,
&ErrorContext::default(),
));
}
let (first_new, second_new) = f(first_old, second_old)?;
self.stack_write(0, Felt::new(first_new));
self.stack_write(1, Felt::new(second_new));
Ok(())
}
}