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start of tape loading. hw works and have a generation script

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Joppe Blondel
2026-10-03 16:29:41 +02:00
parent 47fffc2e71
commit 5897e55094
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apps/README.md
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@@ -7,25 +7,29 @@ directory instead of accessing the UART hardware directly.
The current allocation is:
- `1000-180C`: Tiny BASIC
- `180D-7FFF`: available for more applications (`1900` is the next convenient
- `1400-1C0C`: Tiny BASIC
- `1C0D-2FFF`: available
- `3000-301D`: tape loader
- `301E-7FFF`: available for more applications (`3100` is the next convenient
aligned origin)
The resident BIOS and monitor own high RAM at `C000-FFFF`. Tiny BASIC owns
`8000-BFFF` for its workspace and stack. A future application may reuse Tiny
BASIC's lower-RAM allocation because ROM applications run one at a time, but it
must leave `C000-FFFF` untouched.
`8000-BFFF` for its workspace and stack. Applications may reuse this lower-RAM
allocation because they run one at a time, but they must leave `C000-FFFF`
untouched.
Applications using the interrupt-driven console must leave interrupt mode 2,
the `I` register, and the BIOS UART/CTC configuration intact. They may return
normally if they preserve the caller's stack, or jump to `BIOS_MONITOR` for a
non-returning monitor warm start after replacing the stack pointer.
Use `BIOS_BANK` and `BIOS_ROM_DISABLE` for the write-only banking latch rather
than writing port `00` directly. The BIOS keeps the ROM-disable state when the
RAM bank selection changes. A ROM application must not expect a normal `RET`
after it maps out the ROM containing its return address.
Use `BIOS_BANK`, `BIOS_ROM_DISABLE`, and `BIOS_ROM_ENABLE` for the write-only
banking latch rather than writing port `00` directly. The BIOS keeps the
ROM-disable state when the RAM bank selection changes. A ROM application must
not expect a normal `RET` after it maps out the ROM containing its return
address.
To add an application, add its assembler target and ROM offset to the Makefile,
overlay its binary in the `monitor.prog.bin` recipe, and add a monitor command
or use `G address` to launch it.
Application origins and the resident-memory layout are defined centrally in
`rom_layout.mk`. The build turns that file into C and assembly includes. To add
an application, add its address there, add its build and overlay rules to the
Makefile, and add a monitor command or use `G address` to launch it.