ARM VFP是使用名为HOL4 (Higher Order Logic) 的定理证明器进行形式验证的。以下是一个简单的HOL4示例:
val VFP_spec =
let
(* Specification of the VFP add instruction *)
val add_spec =
let
val rd = mk_reg "rd" (mk_type "word32")
val rn = mk_reg "rn" (mk_type "word32")
val rm = mk_reg "rm" (mk_type "word32")
val cpsr = mk_reg "cpsr" (mk_type "arm_pstate")
val carry = mk_reg "carry" (mk_type "bool")
val overflow = mk_reg "overflow" (mk_type "bool")
val instr = mk_vfp_instr ADD rd rn rm cpsr carry overflow
val semantics = mk_vfp_add_semantics rd rn rm cpsr carry overflow
val precond = mk_true
val postcond = mk_eq (reg_state rd) semantics
val spec =
mk_specification
(mk_eq (instr_state instr) precond)
(mk_eq (instr_state (mk_nop_instr)) postcond)
in
spec
end
in
[add_spec]
end
这个示例定义了一个VFP add 指令的规范。它创建了一个HOL4规范对象,其中包含指令的前置条件、后置条件和语义表示。该规范可以被传递给HOL4的验证器以进行形式验证。