		Search-engine friendly clone of the ACL2 documentation.

States

Inc4-pc

Increment the program counter by 4.

Signature
(inc4-pc stat feat) → new-stat
Arguments: stat — Guard (statp stat).; feat — Guard (featp feat).
Returns: new-stat — Type (statp new-stat).

In the normal instruction encodings, instructions take 32 bits each. Thus, it is common to increment the program counter by 4 (bytes), which this function provides a concise way to do.

We read the program counter, we add 4, and we write the result. Recall that write-pc wraps around if needed [ISA:1.4].

Definitions and Theorems

Function: inc4-pc

(defun inc4-pc (stat feat)
  (declare (xargs :guard (and (statp stat) (featp feat))))
  (declare (xargs :guard (stat-validp stat feat)))
  (let ((__function__ 'inc4-pc))
    (declare (ignorable __function__))
    (write-pc (+ (read-pc stat feat) 4)
              stat feat)))

Theorem: statp-of-inc4-pc

(defthm statp-of-inc4-pc
  (b* ((new-stat (inc4-pc stat feat)))
    (statp new-stat))
  :rule-classes :rewrite)

Theorem: stat-validp-of-inc4-pc

(defthm stat-validp-of-inc4-pc
  (implies (stat-validp stat feat)
           (b* ((?new-stat (inc4-pc stat feat)))
             (stat-validp new-stat feat))))

Theorem: inc4-pc-of-stat-fix-stat

(defthm inc4-pc-of-stat-fix-stat
  (equal (inc4-pc (stat-fix stat) feat)
         (inc4-pc stat feat)))

Theorem: inc4-pc-stat-equiv-congruence-on-stat

(defthm inc4-pc-stat-equiv-congruence-on-stat
  (implies (stat-equiv stat stat-equiv)
           (equal (inc4-pc stat feat)
                  (inc4-pc stat-equiv feat)))
  :rule-classes :congruence)

Theorem: inc4-pc-of-feat-fix-feat

(defthm inc4-pc-of-feat-fix-feat
  (equal (inc4-pc stat (feat-fix feat))
         (inc4-pc stat feat)))

Theorem: inc4-pc-feat-equiv-congruence-on-feat

(defthm inc4-pc-feat-equiv-congruence-on-feat
  (implies (feat-equiv feat feat-equiv)
           (equal (inc4-pc stat feat)
                  (inc4-pc stat feat-equiv)))
  :rule-classes :congruence)