Robert Allan JamesandClaude Sonnet 5
1f3ec3554e
Scope decided with Captain Bob before implementation: ring buffer + recall on today's full-screen vt100 grid, not also confining REPL text to the 4.4o 640x480 box (that confinement stays open as its own future item, not a third silent deferral). No keyboard input path exists yet (M8 unstarted), so the trigger is two new FORTH words, SCROLL-BACK ( n -- ) / SCROLL-FWD ( n -- ), exercised via serial injection. vt100.c gains a text-only 1000-line ring buffer (kmalloc'd, tens of KB -- not pixel snapshots, which would be ~1000x larger for no benefit) plus a shadow buffer mirroring the current screen. scroll_up() now pushes evicted rows into the ring before the pixel scroll. History is one continuous sequence (ring then shadow); scrolling always redraws from that sequence -- no separate pixel-scroll path for scrollback, decided up front to avoid retrofitting later. New src/word_source/scroll_words.c (Module 31), thin wrappers over console_fb_scroll_back()/_fwd() -> vt100_scroll_back()/_fwd(). Bug caught during live testing: both words initially used an off-by-one underflow check (dsp < 1) copied from a different, older dsp convention elsewhere in this codebase; vm_pop() (which these words actually call) uses dsp as a 0-based top-of-stack index, so the check rejected every legitimate single-argument call. Fixed by removing the separate precheck and relying on vm_pop()'s own guard. Live-verified on all three architectures (exceeds this item's amd64-minimum bar): generated 50+ lines via a FORTH loop, confirmed SCROLL-BACK recovers correctly older content, and on amd64 confirmed SCROLL-FWD returns to genuinely live state (not a frozen snapshot) by showing the injected commands' own echo. Known limitation confirmed by direct pixel measurement: redrawn lines lose their original SGR color (not stored per-cell) -- text recovers exactly, color does not. Three-arch verified: Failed: 0, dict-hashes identical across all three (values changed correctly from prior items -- two new words were added). Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
114 lines
4.1 KiB
C
114 lines
4.1 KiB
C
/*
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StarForth — Steady-State Virtual Machine Runtime
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Copyright (c) 2023–2025 Robert A. James
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All rights reserved.
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Licensed under the StarForth License, Version 1.0.
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*/
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/**
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* vt100.h — Full-color ANSI / VT100 terminal state machine
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*
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* Sits on top of the framebuffer driver. Call vt100_init() once the
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* framebuffer is ready, then route all character output through vt100_putc().
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*
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* Supported escape sequences
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* ──────────────────────────
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* Cursor movement ESC[H ESC[n;mH ESC[nA ESC[nB ESC[nC ESC[nD
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* Cursor save/restore ESC[s ESC[u (also ESC7 / ESC8)
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* Erase ESC[2J ESC[K ESC[0K ESC[1K ESC[2K
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* SGR attributes ESC[…m (see below)
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*
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* SGR codes
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* ─────────
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* 0 reset all attributes
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* 1 bold (doubles fg brightness)
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* 4 underline
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* 7 reverse video
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* 22 normal intensity
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* 24 underline off
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* 27 reverse off
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* 30–37 set fg to standard ANSI color 0–7
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* 38;2;r;g;b set fg to 24-bit RGB truecolor
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* 38;5;n set fg to 256-color index
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* 39 reset fg to default
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* 40–47 set bg to standard ANSI color 0–7
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* 48;2;r;g;b set bg to 24-bit RGB truecolor
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* 48;5;n set bg to 256-color index
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* 49 reset bg to default
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* 90–97 set fg to bright ANSI color 8–15
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* 100–107 set bg to bright ANSI color 8–15
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*/
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#ifndef STARKERNEL_VT100_H
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#define STARKERNEL_VT100_H
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#include <stdint.h>
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/* Default terminal colors */
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#define VT100_DEFAULT_FG FB_RGB(0xAA, 0xAA, 0xAA) /* light gray */
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#define VT100_DEFAULT_BG FB_RGB(0x00, 0x00, 0x00) /* black */
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/* -----------------------------------------------------------------------
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* Lifecycle
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* --------------------------------------------------------------------- */
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/**
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* Initialize the VT100 terminal.
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* Must be called after fb_init(). Clears the screen and homes the cursor.
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*/
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void vt100_init(void);
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/**
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* FABRIC.md item 4.4j: switch the glyph-draw backend from font_8x16.c to
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* TTF-TEXT's rasterizer for everything drawn from this call onward --
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* boot/POST output before this call stays font_8x16.c, unaffected.
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* Lazily loads the font capsule and its raster cache on first call
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* (no-op on later calls). Recomputes cols/rows for the new cell size and
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* clears the screen, since the two glyph backends use different cell
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* dimensions. TTF point size/cell dimensions decided final by FABRIC.md
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* item 4.4m (20px text, 96px REPL strip). No-op if the font capsule
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* fails to load (stays on font_8x16.c; logged, not fatal).
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*/
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void vt100_enable_ttf(void);
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/**
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* FABRIC.md item 4.4q: move the REPL scrollback view back/forward by
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* @p n lines and redraw. Offset 0 (the default, and where every call
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* eventually returns to) is the live view -- the same content already on
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* screen. Clamped at both ends: back cannot pass the oldest stored line,
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* forward cannot pass the live view. No-op (including no redraw) if the
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* scrollback buffers failed to allocate at vt100_enable_ttf() time, or
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* before TTF mode is active at all.
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*
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* Known limitation: redraw uses the terminal's current default fg/bg,
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* not each line's original SGR color state at the time it was printed
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* (colors aren't stored per-cell) -- text content is recovered exactly,
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* color is not.
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*/
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void vt100_scroll_back(uint32_t n);
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void vt100_scroll_fwd(uint32_t n);
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/* -----------------------------------------------------------------------
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* Character output
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* --------------------------------------------------------------------- */
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/** Feed one byte into the terminal (handles escape sequences transparently). */
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void vt100_putc(char c);
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/** Feed a null-terminated string. */
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void vt100_puts(const char *s);
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/* -----------------------------------------------------------------------
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* Queries
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* --------------------------------------------------------------------- */
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/** Terminal width in character columns. */
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uint32_t vt100_cols(void);
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/** Terminal height in character rows. */
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uint32_t vt100_rows(void);
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#endif /* STARKERNEL_VT100_H */
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