Subversion Repositories Spectranet

[/] [trunk/] [syslib/] [detect.asm] - Blame information for rev 490

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1 490 winston
;The MIT License
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;
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;Copyright (c) 2011 Alistair Cree
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;
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;Permission is hereby granted, free of charge, to any person obtaining a copy
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;of this software and associated documentation files (the "Software"), to deal
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;in the Software without restriction, including without limitation the rights
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;to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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;copies of the Software, and to permit persons to whom the Software is
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;furnished to do so, subject to the following conditions:
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;
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;The above copyright notice and this permission notice shall be included in
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;all copies or substantial portions of the Software.
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;
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;THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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;IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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;FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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;AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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;LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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;OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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;THE SOFTWARE.
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.include        "spectranet.inc"
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;detects the presence of spectranet by setting the border to cyan and reading
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;from the spectranet control register. If the value is different we signal an
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;error by setting the carry flag, else return with carry clear.
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.text
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.globl F_detect_spectranet
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F_detect_spectranet:
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        push bc
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        ld bc,CTRLREG
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        ld a,5  ;cyan
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        ei
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        halt
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        out (0xFE),a
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        in a,(c)
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        and 0x07        ;mask off bits
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        pop bc
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        and a
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        cp 5
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        ret z
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        scf     ;signal error - no spectranet
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        ret