refactor: c/ -> usr/, compiled program blobs out of the source tree

Userland sources live in usr/ (fits the Unix theme better than 'c').
SDCC output .bin blobs land in build/usr/ with the other build artifacts
instead of littering the source dir; programs.asm INCBINs them from there.
Byte-identical ROM.

1 files changed, 19 insertions, 0 deletions

diff --git a/usr/ptest.c b/usr/ptest.c
new file mode 100644
index 0000000..88b7d30
--- /dev/null
+++ b/usr/ptest.c
@@ -0,0 +1,19 @@
+#include "gbos.h"
+/* ptest: exercise the kernel pipe in one process - write some bytes, read them
+   back, then close the write end and confirm the reader sees EOF. */
+void main(void) {
+    unsigned char pr = pipe();
+    unsigned char pw = pr + 1;
+    int c;
+    if (pr == NOFD) { puts("pipe: none free"); nl(); return; }
+    fputc(pw, 'H'); fputc(pw, 'i'); fputc(pw, '!');
+    c = fgetc(pr); putc(c);
+    c = fgetc(pr); putc(c);
+    c = fgetc(pr); putc(c);
+    nl();
+    close(pw);                 /* last writer gone */
+    c = fgetc(pr);
+    if (c < 0) puts("EOF"); else { puts("got "); putc(c); }
+    nl();
+    close(pr);
+}