diff options
Diffstat (limited to 'src/pardes.zig')
| -rw-r--r-- | src/pardes.zig | 72 |
1 files changed, 32 insertions, 40 deletions
diff --git a/src/pardes.zig b/src/pardes.zig index 8d68cf22..691ee345 100644 --- a/src/pardes.zig +++ b/src/pardes.zig @@ -5747,50 +5747,42 @@ pub const Pardes = struct { // the honest description of a buffer on a board with no filesystem. // AND IT BOOTS WITH SOMETHING IN IT. An empty buffer is honest and useless: the three // words that make this board interesting take an address, and a board's address space is - // precisely the thing you cannot guess. So the boot buffer is a tour of it - every - // address below comes from this repository rather than from memory, which is why they are - // worth trusting: the two flash figures and the two RAM ones are the linker script's own - // ORIGINs (`05-zig-p4/build.zig`'s MEMORY block), and the peripheral bases are - // `DR_REG_*` from ESP-IDF's headers as `05-zig-p4/src/hal` uses them. + // precisely the thing you cannot guess. // - // Each command sits alone on its line because an argument list ends at the last argument: - // a trailing comment would be `ExtraArgument`, so the notes go above the lines they - // describe. Run one by putting the cursor on it, `x` to select the line, Tab to execute - - // the same two keystrokes as any other selection, because an output buffer is a file pane - // and these are ordinary words. + // SHORT, because the window is fourteen rows. The first draft opened with four lines of + // prose about there being no operating system, which is true, unhelpful, and cost a + // third of the screen before the first command. One header line earns its place; the + // rest of the screen is addresses. + // + // Each command sits alone on its line because an argument list ends at the last argument + // - a trailing comment would be `ExtraArgument` - so the labels go above. Every address + // is from this repository or from a session that read it on this die: the flash and RAM + // figures are the linker script's own ORIGINs (`05-zig-p4/build.zig`), the peripheral + // bases are the `DR_REG_*` values `05-zig-p4/src/hal` uses, and the two LP addresses at + // the end are named in ESP-IDF's own headers: 0x5011002c is LP_SYSTEM_REG_LP_STORE0, a + // general-purpose retention register that holds what you put in it, and 0x501101a4 is + // LP_SYSTEM_REG_RNG_DATA, the hardware random generator. Between them they demonstrate + // the whole point of a volatile read: one address gives back what was written and the + // other never gives the same answer twice. Both verified on this die. const content = try p.gpa.dupe(u8, - \\pardes on an ESP32-P4. No OS, no filesystem: - \\this buffer is text with nothing behind it. - \\Peek, Poke and Hexdump read the bus itself. - \\Numbers are hex, with or without 0x. - \\ - \\Select a line with x, then Tab to run it. - \\ - \\-- this image in flash: rodata, then code - \\Hexdump 40000020 60 - \\Hexdump 40050000 60 - \\ - \\-- L2MEM: firmware data, then editor heap - \\Hexdump 4ff00000 60 - \\Hexdump 4ff40000 60 + \\x selects a line, Tab runs it. Hex, 0x optional. \\ - \\-- the mask ROM, where ets_printf lives - \\Hexdump 4fc00000 40 - \\ - \\-- UART0: the console you are reading on + \\-- flash: this image's rodata, then its code + \\Hexdump 40000020 40 + \\Hexdump 40050000 40 + \\-- L2MEM: firmware data, then the editor's heap + \\Hexdump 4ff00000 40 + \\Hexdump 4ff40000 40 + \\-- the mask ROM + \\Hexdump 4fc00000 20 + \\-- UART0, the console you are reading this on \\Peek 500ca000 4 - \\ - \\-- systimer. Run twice: a register is not - \\-- memory, and the two reads differ. - \\Peek 500e2000 4 - \\ - \\-- GPIO_OUT, and pad 0's IO_MUX entry - \\Peek 500e0004 - \\Peek 500e1004 - \\ - \\-- Poke needs a value. Harmless: a W1TC - \\-- register clears nothing given no bits. - \\Poke 500e000c 0 + \\-- LP_STORE0: write a word, then read it back + \\Poke 5011002c deadbeef + \\Peek 5011002c + \\-- RNG_DATA: a register is not memory. Run twice. + \\Peek 501101a4 + \\Peek 501101a4 ); errdefer p.gpa.free(content); _ = try output_pane.open(p, 0, "", .{ .cmd = .New }, "", content); |