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Fix Comment Syntax in Code Update storage.cairo #201

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Fix Comment Syntax in Code Update storage.cairo #201

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38 changes: 19 additions & 19 deletions src/starkware/starknet/common/storage.cairo
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Original file line number Diff line number Diff line change
@@ -1,13 +1,13 @@
from starkware.cairo.common.math import assert_250_bit

const MAX_STORAGE_ITEM_SIZE = 256;
// Valid storage addresses should satisfy address + offset < 2**251 where
// offset < MAX_STORAGE_ITEM_SIZE and address < ADDR_BOUND.
# Valid storage addresses should satisfy address + offset < 2**251 where
# offset < MAX_STORAGE_ITEM_SIZE and address < ADDR_BOUND.
const ADDR_BOUND = 2 ** 251 - MAX_STORAGE_ITEM_SIZE;

// Computes addr % ADDR_BOUND so that the result will form a valid storage item address in the
// storage tree. In particular, we need the result + MAX_STORAGE_ITEM_SIZE to be less than
// 2**251.
# Computes addr % ADDR_BOUND so that the result will form a valid storage item address in the
# storage tree. In particular, we need the result + MAX_STORAGE_ITEM_SIZE to be less than
# 2**251.
@known_ap_change
func normalize_address{range_check_ptr}(addr: felt) -> (res: felt) {
tempvar is_small;
Expand All @@ -24,27 +24,27 @@ func normalize_address{range_check_ptr}(addr: felt) -> (res: felt) {
%{ ids.is_250 = 1 if ids.addr < 2**250 else 0 %}
if (is_250 != 0) {
ap += 11;
// In this case addr < 2**250 < ADDR_BOUND, so addr % ADDR_BOUND = addr.
# In this case addr < 2**250 < ADDR_BOUND, so addr % ADDR_BOUND = addr.
assert_250_bit(addr);
} else {
ap += 10;
// In this case 0 <= ADDR_BOUND - 1 - addr < 2**250, so addr < ADDR_BOUND.
# In this case 0 <= ADDR_BOUND - 1 - addr < 2**250, so addr < ADDR_BOUND.
assert_250_bit(ADDR_BOUND - 1 - addr);
}
return (res=addr);
} else {
// The first call to assert_250_bit() checks that 0 <= (addr - ADDR_BOUND) % PRIME < 2**250.
// The second call checks that 0 <= (-1 - addr) % PRIME < 2**250.
// Let x = (addr - ADDR_BOUND) % PRIME and y = (-1 - addr) % PRIME. Then,
// x + y = (addr - ADDR_BOUND) + (-1 - addr) = PRIME - 1 - ADDR_BOUND (mod PRIME).
// So we have:
// x + y = PRIME - 1 - ADDR_BOUND (mod PRIME).
// Since both hands are in the range [0, PRIME) (since 2 * 2**250 < PRIME),
// they must be equal as integers.
// In particular, x + ADDR_BOUND = PRIME - 1 - y < PRIME.
// Since addr = x + ADDR_BOUND (mod PRIME) and both sides are in the range [0, PRIME)
// we have addr = x + ADDR_BOUND (as integers).
// Therefore, we should subtract ADDR_BOUND to get addr % ADDR_BOUND.
# The first call to assert_250_bit() checks that 0 <= (addr - ADDR_BOUND) % PRIME < 2**250.
# The second call checks that 0 <= (-1 - addr) % PRIME < 2**250.
# Let x = (addr - ADDR_BOUND) % PRIME and y = (-1 - addr) % PRIME. Then,
# x + y = (addr - ADDR_BOUND) + (-1 - addr) = PRIME - 1 - ADDR_BOUND (mod PRIME).
# So we have:
# x + y = PRIME - 1 - ADDR_BOUND (mod PRIME).
# Since both hands are in the range [0, PRIME) (since 2 * 2**250 < PRIME),
# they must be equal as integers.
# In particular, x + ADDR_BOUND = PRIME - 1 - y < PRIME.
# Since addr = x + ADDR_BOUND (mod PRIME) and both sides are in the range [0, PRIME)
# we have addr = x + ADDR_BOUND (as integers).
# Therefore, we should subtract ADDR_BOUND to get addr % ADDR_BOUND.
let x = addr - ADDR_BOUND;
let y = (-1) - addr;
assert_250_bit(x);
Expand Down