tests: add hello2, simple, banktest smoke tests

hello2 — stdio vs conio output API comparison (fast/no-attr vs
slower/attributed), also exercises textcolor/textbackground.
simple — packed 2-bit style array bit-twiddling smoke test.
banktest — __banked function calls across two explicit banks in huge
memory mode.

hello2.c updated to call the renamed gettextmode/settextmode (see the
conio rename in 5e5e70d).

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

tests/banktest/Makefile

@@ -0,0 +1,11 @@
+# Build banked.exe — HUGE memory mode (small + banked code in W3).
+#
+# Layout:
+#   CODE/HOME at 0x4100 (W1), DATA at 0x8000 (W2), banks at 0x{N}C000 (W3).
+#   crt0_banked.s loads N banks from the .EXE before calling main.
+
+PROJ_ROOT := $(abspath $(CURDIR)/../..)
+EXAMPLE   := banked
+MEMORY    := huge
+EXTRA_FLAGS := --bank 1=bank1.c --bank 2=bank2.c
+include $(PROJ_ROOT)/app.mk

tests/banktest/bank1.c

@@ -0,0 +1,18 @@
+#include <stdio.h>
+#include <stdint.h>
+#include <sprinter.h>
+
+uint16_t bank1var = 0;
+extern uint16_t bank2var;
+
+void bank1_func(void) __banked
+{
+    printf("BANK1: hello from the first bank, phys page = 0x%02X, var = %u\n", _io_page_w3, bank1var);
+}
+
+void bank1_func2(uint16_t x) __banked
+{
+    printf("BANK1: hello from the first bank, phys page = 0x%02X, set var in SECOND bank to %u\n", _io_page_w3, x);
+    bank2var = x;
+}
+

tests/banktest/bank2.c

@@ -0,0 +1,11 @@
+#include <stdio.h>
+#include <stdint.h>
+#include <sprinter.h>
+
+uint16_t bank2var = 0;
+
+void bank2_func(void) __banked
+{
+    printf("BANK2: hello from the second bank, phys page = 0x%02X, var = %u\n", _io_page_w3, bank2var);
+}
+

tests/banktest/banked.c

@@ -0,0 +1,34 @@
+#include <stdio.h>
+#include <stdint.h>
+#include <sprinter.h>
+
+/* crt0_banked.s reads this constant to know how many banks to load. */
+const uint8_t n_banks = 2;
+
+void bank1_func(void) __banked;
+void bank2_func(void) __banked;
+void bank1_func2(uint16_t) __banked;
+
+extern uint16_t bank1var;
+extern uint16_t bank2var;
+
+extern uint8_t bank_pages[];   /* filled by crt0_banked.s */
+
+int main(void)
+{
+    bank1var = 1;
+    bank2var = 2;
+    puts("HOME: program start.");
+    printf("HOME: window 3 phys page = 0x%02X\n", _io_page_w3);
+    printf("HOME: bank_pages[1] = 0x%02X\n", bank_pages[1]);
+    printf("HOME: bank_pages[2] = 0x%02X\n", bank_pages[2]);
+
+    bank1_func();
+    bank2_func();
+    bank1_func2(25);
+    bank2_func();
+
+    puts("Press any key to exit...");
+    (void)getchar();
+    return 0;
+}

tests/hello2/Makefile

@@ -0,0 +1,5 @@
+# Build hello.exe — uses lib/sprinter.lib in TINY memory mode.
+
+PROJ_ROOT := $(abspath $(CURDIR)/../..)
+EXAMPLE   := hello2
+include $(PROJ_ROOT)/app.mk

tests/hello2/hello2.c

@@ -0,0 +1,82 @@
+/*
+ * hello — smoke test for the two output APIs:
+ *
+ *   stdio (printf/puts/putchar)  — FAST, no attribute (ambient colour)
+ *   conio (cprintf/cputs/putch)  — SLOWER, applies textcolor/textbackground
+ *
+ * Demonstrates textcolor/textbackground (Turbo-C-compatible names).
+ */
+
+#include <stdio.h>
+#include <conio.h>
+#include <gfx.h>
+#include <sprinter.h>
+#include <sprinter_exit.h>
+#include <errno.h>
+
+int main(void)
+{
+    errno = -1;
+    int16_t a0 = 0, a1 = 0;
+    a0 = get_text_attr();
+
+    uint8_t vMode = gettextmode();
+    settextmode(TEXT_MODE_80x32);
+
+    /* Wipe the screen with a known attribute so stdio printf/puts inherit
+     * a clean colour for the cursor. */
+    clrscr_attr(COLOR(COLOR_LIGHTGRAY, COLOR_BLACK));
+
+    /* --- stdio set: fast, no attribute ------------------------------- */
+    puts("hello (stdio) - fast PCHARS, ambient colour");
+    printf("printf: a0=%d (initial attr)\n", a0);
+
+    /* --- conio set: applies textcolor / textbackground --------------- */
+    textcolor(COLOR_YELLOW);
+    textbackground(COLOR_BLUE);
+    cputs("conio: yellow on blue\r\n");
+
+    printf("printf: a0=%d (initial attr)\n", a0);
+
+    textcolor(COLOR_LIGHTRED);
+    textbackground(COLOR_BLACK);
+    cprintf("cprintf %d %d %s\r\n", 42, -7, "args");
+
+    printf("printf: a0=%d (initial attr)\n", a0);
+
+    /* set_text_attr / textattr replace the whole byte. */
+    textattr(COLOR(COLOR_LIGHTGREEN, COLOR_BLACK));
+    cputs("conio: light-green via textattr\r\n");
+
+    printf("printf: a0=%d (initial attr)\n", a0);
+
+    /* Opting out of attribute control — conio falls back to fast path. */
+    set_text_attr(KEEP_EXIST_ATTR);
+    cputs("conio with KEEP_EXIST_ATTR (fast path)\r\n");
+
+    printf("printf: a0=%d (initial attr)\n", a0);
+
+    a1 = get_text_attr();
+
+    printf("printf: a0=%d (initial attr)\n", a0);
+
+    /* Back to a normal attribute so the goodbye reads cleanly. */
+    textattr(COLOR(COLOR_LIGHTCYAN, COLOR_BLACK));
+
+    printf("printf: a0=%d (initial attr)\n", a0);
+
+    cprintf("a0=%d a1=%d now=%d errno=%d\n\r",
+           a0, a1, get_text_attr(), errno);
+    // cprintf("a0=%d a1=%d",
+    //        a0, a1);
+    // cprintf(" now=%d errno=%d\n\r",
+    //        get_text_attr(), errno);
+#ifdef DEBUG_RT
+    printf("w2_self_allocated = %u\n", w2_self_allocated);
+#endif
+    cputs("Press any key to exit...");
+
+    (void)getchar();
+    settextmode(vMode);
+    return 0;
+}

tests/simple/Makefile

@@ -0,0 +1,5 @@
+# Build hello.exe — uses lib/sprinter.lib in TINY memory mode.
+
+PROJ_ROOT := $(abspath $(CURDIR)/../..)
+EXAMPLE   := simple
+include $(PROJ_ROOT)/app.mk

tests/simple/simple.c

@@ -0,0 +1,46 @@
+/*
+ * hello — smoke test for the two output APIs:
+ *
+ *   stdio (printf/puts/putchar)  — FAST, no attribute (ambient colour)
+ *   conio (cprintf/cputs/putch)  — SLOWER, applies textcolor/textbackground
+ *
+ * Demonstrates textcolor/textbackground (Turbo-C-compatible names).
+ */
+
+#include <stdio.h>
+#include <conio.h>
+#include <gfx.h>
+#include <sprinter.h>
+#include <sprinter_exit.h>
+#include <errno.h>
+
+static uint8_t buff[] = {0xE4, 0x1B};
+
+uint8_t get_style(uint32_t idx) {
+    return (uint8_t)((buff[idx >> 2] >> ((idx & 3) << 1)) & 3u);
+}
+
+void set_style(uint32_t idx, uint8_t style) {
+    buff[idx >> 2] = buff[idx >> 2] & ~(3u << ((idx & 3) << 1)) | ((style & 3u) << ((idx & 3) << 1));
+}
+
+int main(void)
+{
+    for(int i = 0; i < 8; i++) {
+        dec8(get_style(i));
+        puts("");
+    }
+
+    for(int i = 0; i < 8; i++) {
+        set_style(i, (i + 1) & 3);
+    }
+    puts("");
+    for(int i = 0; i < 8; i++) {
+        dec8(get_style(i));
+        puts("");
+    }
+
+    cputs("Press any key to exit...");
+    (void)getchar();
+    return 0;
+}