; Validate ascending order without modifying sort counters.
VALID_SORT:
        PRE     IX,SORT_NVAL
        LDW     $16,(IX+$SX)
        SBW     $16,$SY
        JR      Z,VAL_OK
        PRE     IX,SORT_MVAL
        LDW     $8,(IX+$SX)
        LDW     $12,SORT_BASE
        LDW     $14,$12
        ADW     $14,$8
VAL_LOOP:
        LDW     $20,$12
        LDW     $22,$14
        LDW     $24,$8
        CAL     CMP_RAW
        SBC     $0,1
        JR      Z,VAL_FAIL
        ADW     $12,$8
        ADW     $14,$8
        SBW     $16,$SY
        JP      NZ,VAL_LOOP
VAL_OK:
        LD      $0,0
        RTN
VAL_FAIL:
        LD      $0,1
        RTN