printf->__INTERNAL_fmt. FD passed via RAX. fwrite now allows specifiers and variable arguments.

src/file.asm

@@ -1,5 +1,7 @@
 %include "src/constants.asm"
 
+extern	__INTERNAL_fmt
+
 extern	strlen
 extern	umask_get
 
@@ -76,7 +78,7 @@ fopen:
 	call	fexist
 	pop	rsi
 	pop	rdi
-	mov	rax, 1
+	test	rax, 1
 	jz	%%createFile
 	jmp	%1
 	%%createFile:
@@ -86,7 +88,7 @@ fopen:
 	pop	rdi
 	push	rdi
 	not	rax
-	mov	rsi, 00666q
+	mov	rsi, 0666q
 	and	rsi, rax
 	mov	rax, NR_creat
 	syscall
@@ -155,6 +157,7 @@ fopen:
 ;	rax*	(ret)
 ;	rdi	(arg) Pointer to opened file
 fclose:
+	sub	rsp, SIZE_QWORD
 	cmp	rdi, 3
 	jl	.invalid_fd ;disallow closing stdin,stdout,stderr
 	mov	rax, NR_close
@@ -165,6 +168,7 @@ fclose:
 	mov	rax, -EINVAL
 
 	.quit:
+	add	rsp, SIZE_QWORD
 	ret
 
 ;----- fexist(*file[]) -----;
@@ -174,7 +178,7 @@ fclose:
 ;	rax*	(ret)
 ;	rdi	(arg) Pointer to string holding (path+)file name
 fexist:
-	;sub	rsp, SIZE_QWORD
+	sub	rsp, SIZE_QWORD
 	mov	rsi, 'r'
 	call	fopen
 	test	rax, rax
@@ -186,35 +190,32 @@ fexist:
 	.not_exist:
 	xor	rax, rax
 	.quit:
-	;add	rsp, SIZE_QWORD
+	add	rsp, SIZE_QWORD
 	ret
 
-;--- fwrite(*filePointer, *data[]) -----;
-; Writes data to given file
+;--- fwrite(*filePointer, *data[], ...) -----;
+; Writes data to given file. Allows format specifiers and variable arguments (see `__INTERNAL_fmt` for supported specifiers)
 ; Return value: Length of given string(data[]), 0 if nothing was written (eg invalid file or file not writable, or data[] is empty)
 ; Used registers:
 ;	rax*	(ret)
 ;	rdi	(arg) Pointer to file
 ;	rsi	(arg) Data to write
-;	r8*	Backs up rdi
-;	r9*	Backs up rsi
 fwrite:
-	sub	rsp, SIZE_QWORD
+	push	rbp
+	mov	rbp, rsp
+	cmp	rdi, 2
+	jg	.cnt
 	xor	rax, rax
-	cmp	rdi, 3
-	jl	.quit
-	mov	r8, rdi
-	mov	r9, rsi
-
-	mov	rdi, rsi
-	call	strlen
-
-	mov	rdx, rax
-	mov	rax, NR_write
-	mov	rdi, r8
-	mov	rsi, r9
-	syscall
-
-	.quit:
-	add	rsp, SIZE_QWORD
+	leave
+	ret
+	.cnt:
+	mov	rax, rdi
+	mov	rdi, rsi
+	mov	rsi, rdx
+	mov	rdx, rcx
+	mov	rcx, r8
+	mov	r8, r9
+	mov	r9, [rbp + RBP_OFFSET_CALLER]
+	call	__INTERNAL_fmt
+	leave
 	ret