Rewrite fputs in assembly

-28 bytes, -1% cycles

libsrc/common/fputs.s

@@ -0,0 +1,42 @@
+;
+; Colin Leroy-Mira, 2024
+;
+; int __fastcall__ fputs (const char* s, register FILE* f)
+;
+
+        .export         _fputs
+        .importzp       ptr1, ptr2
+        .import         _write, _strlen
+        .import         swapstk, pushax, returnFFFF
+
+        .include        "stdio.inc"
+        .include        "_file.inc"
+
+_fputs:
+        sta     ptr1
+        stx     ptr1+1
+
+        ldy     #_FILE::f_flags
+        lda     (ptr1),y
+        tax
+        and     #_FOPEN         ; Check for file open
+        beq     ret_eof
+        txa
+        and     #(_FERROR|_FEOF); Check for error/eof
+        bne     ret_eof
+
+        ; Push _write parameters
+        ldy     #_FILE::f_fd
+        lda     (ptr1),y
+        ldx     #$00
+        jsr     swapstk         ; Push fd, get s
+
+        jsr     pushax          ; Push s
+
+        jsr     _strlen         ; Get length
+
+        ; Write
+        jmp     _write
+
+ret_eof:
+        jmp     returnFFFF

test/ref/test_fputs.c

@@ -0,0 +1,40 @@
+/*
+  !!DESCRIPTION!! fgets test
+  !!LICENCE!!     Public domain
+*/
+
+#include "common.h"
+
+#include <ctype.h>
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+FILE *in, *out;
+char buf[512], err;
+
+#define INFILE   "cf.in"
+
+int main(int argc,char **argv)
+{
+    in = fopen(INFILE, "rb");
+    if (in == NULL) {
+        return EXIT_FAILURE;
+    }
+
+    strcpy(buf, "test");
+    if (fputs(buf, in) != EOF) {
+      printf("Error: can fputs to a file opened for reading\n");
+      return EXIT_FAILURE;
+    }
+    clearerr(in);
+
+    while (fgets(buf, 512, in) != NULL) {
+      fputs(buf, stdout);
+    }
+
+    fclose(in);
+    return 0;
+}