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Semantics

Exec-sh

Semantics of the SH instruction [ISA:2.6].

Signature
(exec-sh rs1 rs2 imm stat feat) → new-stat
Arguments: rs1 — Guard (ubyte5p rs1).; rs2 — Guard (ubyte5p rs2).; imm — Guard (ubyte12p imm).; stat — Guard (statp stat).; feat — Guard (featp feat).
Returns: new-stat — Type (statp new-stat).

We calculate the effective address. We read the low 16 bits of rs2 as an unsigned 16-bit integer. We write the integer to the effective address. We increment the program counter.

Definitions and Theorems

Function: exec-sh

(defun exec-sh (rs1 rs2 imm stat feat)
  (declare (xargs :guard (and (ubyte5p rs1)
                              (ubyte5p rs2)
                              (ubyte12p imm)
                              (statp stat)
                              (featp feat))))
  (declare (xargs :guard (stat-validp stat feat)))
  (let ((__function__ 'exec-sh))
    (declare (ignorable __function__))
    (b* ((addr (eff-addr rs1 imm stat feat))
         (val (loghead 16
                       (read-xreg-unsigned (ubyte5-fix rs2)
                                           stat feat)))
         (stat (write-memory-unsigned16 addr val stat feat))
         (stat (inc4-pc stat feat)))
      stat)))

Theorem: statp-of-exec-sh

(defthm statp-of-exec-sh
  (b* ((new-stat (exec-sh rs1 rs2 imm stat feat)))
    (statp new-stat))
  :rule-classes :rewrite)

Theorem: stat-validp-of-exec-sh

(defthm stat-validp-of-exec-sh
  (implies (stat-validp stat feat)
           (b* ((?new-stat (exec-sh rs1 rs2 imm stat feat)))
             (stat-validp new-stat feat))))

Theorem: exec-sh-of-ubyte5-fix-rs1

(defthm exec-sh-of-ubyte5-fix-rs1
  (equal (exec-sh (ubyte5-fix rs1)
                  rs2 imm stat feat)
         (exec-sh rs1 rs2 imm stat feat)))

Theorem: exec-sh-ubyte5-equiv-congruence-on-rs1

(defthm exec-sh-ubyte5-equiv-congruence-on-rs1
  (implies (ubyte5-equiv rs1 rs1-equiv)
           (equal (exec-sh rs1 rs2 imm stat feat)
                  (exec-sh rs1-equiv rs2 imm stat feat)))
  :rule-classes :congruence)

Theorem: exec-sh-of-ubyte5-fix-rs2

(defthm exec-sh-of-ubyte5-fix-rs2
  (equal (exec-sh rs1 (ubyte5-fix rs2)
                  imm stat feat)
         (exec-sh rs1 rs2 imm stat feat)))

Theorem: exec-sh-ubyte5-equiv-congruence-on-rs2

(defthm exec-sh-ubyte5-equiv-congruence-on-rs2
  (implies (ubyte5-equiv rs2 rs2-equiv)
           (equal (exec-sh rs1 rs2 imm stat feat)
                  (exec-sh rs1 rs2-equiv imm stat feat)))
  :rule-classes :congruence)

Theorem: exec-sh-of-ubyte12-fix-imm

(defthm exec-sh-of-ubyte12-fix-imm
  (equal (exec-sh rs1 rs2 (ubyte12-fix imm)
                  stat feat)
         (exec-sh rs1 rs2 imm stat feat)))

Theorem: exec-sh-ubyte12-equiv-congruence-on-imm

(defthm exec-sh-ubyte12-equiv-congruence-on-imm
  (implies (acl2::ubyte12-equiv imm imm-equiv)
           (equal (exec-sh rs1 rs2 imm stat feat)
                  (exec-sh rs1 rs2 imm-equiv stat feat)))
  :rule-classes :congruence)

Theorem: exec-sh-of-stat-fix-stat

(defthm exec-sh-of-stat-fix-stat
  (equal (exec-sh rs1 rs2 imm (stat-fix stat)
                  feat)
         (exec-sh rs1 rs2 imm stat feat)))

Theorem: exec-sh-stat-equiv-congruence-on-stat

(defthm exec-sh-stat-equiv-congruence-on-stat
  (implies (stat-equiv stat stat-equiv)
           (equal (exec-sh rs1 rs2 imm stat feat)
                  (exec-sh rs1 rs2 imm stat-equiv feat)))
  :rule-classes :congruence)

Theorem: exec-sh-of-feat-fix-feat

(defthm exec-sh-of-feat-fix-feat
  (equal (exec-sh rs1 rs2 imm stat (feat-fix feat))
         (exec-sh rs1 rs2 imm stat feat)))

Theorem: exec-sh-feat-equiv-congruence-on-feat

(defthm exec-sh-feat-equiv-congruence-on-feat
  (implies (feat-equiv feat feat-equiv)
           (equal (exec-sh rs1 rs2 imm stat feat)
                  (exec-sh rs1 rs2 imm stat feat-equiv)))
  :rule-classes :congruence)