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; basic test of OTIR block-transfer instruction

;

; initializes a memory region and then transfers that region

; to an accumulator

    .module otir

;--------------------------------------------------------

; special function registers

;--------------------------------------------------------

_sim_ctl_port   =       0x0080

_msg_port       =       0x0081

_timeout_port   =       0x0082

_max_timeout_low        =       0x0083

_max_timeout_high       =       0x0084

_intr_cntdwn    =       0x0090

_cksum_value    =       0x0091

_cksum_accum    =       0x0092

_inc_on_read    =       0x0093

    .area INIT (ABS)

    .org  0

    jp      init

init:

    ld      sp, #0xffff

    ;; initialize dbuf memory area with regular pattern

    ;; pattern starts with 1 and increments

    ld      hl, #dbuf

    ld      b, #255

    ld      c, #1

dbuf_init:

    ld      (hl), c

    inc     hl

    inc     c

    djnz    dbuf_init

    call    reset_timeout

    ld      b, #16

    call    xfer_test

    call    reset_timeout

    ld      b, #63

    call    xfer_test

    call    reset_timeout

    ld      b, #127

    call    xfer_test

    call    reset_timeout

    ld      b, #128

    call    xfer_test

    call    reset_timeout

    ld      b, #254

    call    xfer_test

    call    reset_timeout

    ld      b, #255

    call    xfer_test

    ;; finish simulation with test passed

    ld      a, #1

    out     (_sim_ctl_port), a

    ret

    ;; test sending X amount of data from the buffer to the

    ;; accumulator.  Amount of data to transfer is in B.

    ;; After tranferring data to checksummer, perform

    ;; checksum and compare

xfer_test:

    push    bc

    ld      hl, #dbuf

    ld      a, #0

    out     (_cksum_value), a

    ld      c, #_cksum_accum

    otir

    ;; do checksum over same region

    pop     bc

    ld      hl, #dbuf

    ld      a, #0

xfer_test_cksum:

    add     a, (hl)

    inc     hl

    djnz    xfer_test_cksum

    ;; store calc'ed checksum in D and read out cksum register

    ld      d, a

    in      a, (_cksum_value)

    ;; compare two values and fail test if not equal

    cp      d

    jp      nz, xfer_fail

    ret

xfer_fail:

    ld      a, #2

    out     (_sim_ctl_port), a

    ret

reset_timeout:

    ld      a, #2

    out     (_timeout_port), a

    ret

    .org    0x8000

dbuf:

    .ds     256