nx_strfmt.nx

nx_strfmt.nx -- minimal printf-style formatter. Replaces the dozens of ad-hoc `out_str` + `out_int64` chains scattered across the runtime with one canonical "format string + args" interface. Format directives supported (printf subset): %d signed decimal i64 %u unsigned decimal i64 %x lowercase hex i64 (no 0x prefix) %X uppercase hex i64 %s NUL-terminated *u8 %c single byte (low 8 bits of i64) %p pointer (= 0x + 16-char zero-padded hex) %% literal '%' Width / precision / alignment NOT supported (v0.0.1). Add when the codegen-disassembler-debugger triangle needs prettier output. Three entry points: nx_fmt_to_buf(out, cap, fmt, argv, argc) Writes into a caller buffer; returns bytes written. nx_fmt_to_fd(fd, fmt, argv, argc) Writes directly to fd via sys_write; returns total bytes. nx_fmt_int / nx_fmt_hex / nx_fmt_bytes (low-level helpers) Args are passed as a *i64 array of length argc. Each %d / %u / %x / %X / %p / %c consumes one slot (i64). %s consumes one slot (interpreted as *u8). Why this design (vs varargs): Varargs in NishiLang would need ABI work; a flat i64 array is already the calling convention for ir_emit_call internally. Caller does: let argv: *i64 = sys_mmap(8 * 4)