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e4a4a9800d
It's a bit more inconvenient in terms of register protection (BC is much more generally useful than IY), but it makes tight spots such as next and execute much faster, so I think it's worth it.
17 lines
692 B
Plaintext
17 lines
692 B
Plaintext
Z80 boot code
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This assembles the boot binary. It requires the Z80 assembler
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(B200) and cross compilation setup (B260). It requires some
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constants to be set. See B420 for details.
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RESERVED REGISTERS: At all times, IX points to RSP TOS and BC
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is IP. SP points to PSP TOS, but you can still use the stack
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in native code. you just have to make sure you've restored it
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before "next".
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STABLE ABI: The boot binary starts with a list of references.
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The address of these references have to stay to those addr-
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esses. The rest of the Collapse OS code depend on it. In fact,
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up until 0x67, the (?br) wordref, pretty much everything has
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to stay put. (cont.)
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