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Semantics32

Exec32-sh

Semantics of the SH instruction [ISA:2.6].

Signature
(exec32-sh rs1 rs2 imm stat) → new-stat
Arguments: rs1 — Guard (ubyte5p rs1).; rs2 — Guard (ubyte5p rs2).; imm — Guard (ubyte12p imm).; stat — Guard (stat32ip stat).
Returns: new-stat — Type (stat32ip new-stat).

Only little endian is supported for now.

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: exec32-sh

(defun exec32-sh (rs1 rs2 imm stat)
  (declare (xargs :guard (and (ubyte5p rs1)
                              (ubyte5p rs2)
                              (ubyte12p imm)
                              (stat32ip stat))))
  (let ((__function__ 'exec32-sh))
    (declare (ignorable __function__))
    (b* ((addr (eff32-addr rs1 imm stat))
         (val (loghead 16 (read32-xreg-unsigned rs2 stat)))
         (stat (write32-mem-ubyte16-lendian addr val stat))
         (stat (inc32-pc stat)))
      stat)))

Theorem: stat32ip-of-exec32-sh

(defthm stat32ip-of-exec32-sh
  (b* ((new-stat (exec32-sh rs1 rs2 imm stat)))
    (stat32ip new-stat))
  :rule-classes :rewrite)

Theorem: exec32-sh-of-ubyte5-fix-rs1

(defthm exec32-sh-of-ubyte5-fix-rs1
  (equal (exec32-sh (ubyte5-fix rs1)
                    rs2 imm stat)
         (exec32-sh rs1 rs2 imm stat)))

Theorem: exec32-sh-ubyte5-equiv-congruence-on-rs1

(defthm exec32-sh-ubyte5-equiv-congruence-on-rs1
  (implies (ubyte5-equiv rs1 rs1-equiv)
           (equal (exec32-sh rs1 rs2 imm stat)
                  (exec32-sh rs1-equiv rs2 imm stat)))
  :rule-classes :congruence)

Theorem: exec32-sh-of-ubyte5-fix-rs2

(defthm exec32-sh-of-ubyte5-fix-rs2
  (equal (exec32-sh rs1 (ubyte5-fix rs2)
                    imm stat)
         (exec32-sh rs1 rs2 imm stat)))

Theorem: exec32-sh-ubyte5-equiv-congruence-on-rs2

(defthm exec32-sh-ubyte5-equiv-congruence-on-rs2
  (implies (ubyte5-equiv rs2 rs2-equiv)
           (equal (exec32-sh rs1 rs2 imm stat)
                  (exec32-sh rs1 rs2-equiv imm stat)))
  :rule-classes :congruence)

Theorem: exec32-sh-of-ubyte12-fix-imm

(defthm exec32-sh-of-ubyte12-fix-imm
  (equal (exec32-sh rs1 rs2 (ubyte12-fix imm)
                    stat)
         (exec32-sh rs1 rs2 imm stat)))

Theorem: exec32-sh-ubyte12-equiv-congruence-on-imm

(defthm exec32-sh-ubyte12-equiv-congruence-on-imm
  (implies (acl2::ubyte12-equiv imm imm-equiv)
           (equal (exec32-sh rs1 rs2 imm stat)
                  (exec32-sh rs1 rs2 imm-equiv stat)))
  :rule-classes :congruence)

Theorem: exec32-sh-of-stat32i-fix-stat

(defthm exec32-sh-of-stat32i-fix-stat
  (equal (exec32-sh rs1 rs2 imm (stat32i-fix stat))
         (exec32-sh rs1 rs2 imm stat)))

Theorem: exec32-sh-stat32i-equiv-congruence-on-stat

(defthm exec32-sh-stat32i-equiv-congruence-on-stat
  (implies (stat32i-equiv stat stat-equiv)
           (equal (exec32-sh rs1 rs2 imm stat)
                  (exec32-sh rs1 rs2 imm stat-equiv)))
  :rule-classes :congruence)