Comparison

EQ, LT, GT, LTE and GTE compare two signed i64 values and push exactly 1 (true) or 0 (false). Byte values, operand layouts and stack effects are in the Comparison section of the opcode reference. None of these instructions touch a register, and none of them can fail beyond the ordinary StackUnderflow every popping instruction shares; every i64 value is comparable to every other.

The Iverson bracket notation \([P]\), used throughout this book, equals \(1\) if \(P\) is true and \(0\) otherwise; EQ a b is exactly \([a = b]\), and the other four follow the same pattern.

Boolean Convention

XQVM uses the integer convention for booleans: 0 is false, any non-zero value is true. Comparison instructions always produce exactly 1 or 0, never some other non-zero encoding of “true”, which is what makes their output directly usable as a JUMPI condition or as an operand to Logical AND/OR/XOR/NOT without an extra normalisation step. PUSH 3; PUSH 5; LT pushes 1, and PUSH 3; PUSH 5; GT pushes 0, both read back through STOW/OUTPUT.