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

src/console.asm

@@ -11,6 +11,8 @@ section .bss
 	printfBuff	resb	printfBuffLen
 	printfArgs	resq	5 ;5=>rsi,rdx,rcx,r8,r9
 section .text
+	global	__INTERNAL_fmt
+
 	global	print
 	global	puts
 	global	printf
@@ -94,13 +96,23 @@ puts:
 ;	r12	Padding length
 ;	r13	Bitmask, 1 = insert specifier yes/no, 2 = use zeroes for padding yes/no
 ;	r14	Keeps track of amount of processed format specifiers
+;	r15	Stores fd to write output to (passed to __INTERNAL_fmt via RAX)
 printf:
+	mov	rax, FD_stdout
+	jmp	__INTERNAL_fmt
+
+__INTERNAL_fmt:
 	%macro load_arg 1
 	cmp	r14, 4
 	ja	%%fromStack
 	mov	%1, [printfArgs + SIZE_QWORD * r14]
 	jmp	%%continue
 	%%fromStack:
+	cmp	r15, FD_stdout
+	je	%%stackNoShift
+	mov	%1, [rbp + (RBP_OFFSET_CALLER*2 + SIZE_QWORD) + ((r14-5) * SIZE_QWORD)] ;non-printf functions calling __INTERNAL_fmt require RDI to be FD, all args shifted and rbp+RBP_OFFSET_CALLER to r9. Also requires function prologue and a CALL to __INTERNAL_fmt (not a JMP like in printf); hence the RBP_OFFSET_CALLER*2
+	jmp	%%continue
+	%%stackNoShift:
 	mov	%1, [rbp + RBP_OFFSET_CALLER + ((r14-5) * SIZE_QWORD)]
 	%%continue:
 	%endmacro
@@ -152,10 +164,11 @@ printf:
 	; entry:
 	push	rbp
 	mov	rbp, rsp
-	sub	rsp, SIZE_QWORD
 	push	r12
 	push	r13
 	push	r14
+	push	r15
+	mov	r15, rax
 
 	cmp	byte [rdi], EOS
 	je	.emptyStr
@@ -414,7 +427,7 @@ printf:
 	push	rdx
 	push	r11
 	mov	rax, NR_write
-	mov	rdi, FD_stdout
+	mov	rdi, r15
 	lea	rsi, [rel printfBuff]
 	mov	rdx, r10
 	syscall
@@ -435,7 +448,7 @@ printf:
 
 	.wrapup:
 	mov	rax, NR_write
-	mov	rdi, FD_stdout
+	mov	rdi, r15
 	lea	rsi, [rel printfBuff]
 	mov	rdx, r10
 	mov	r10, r11
@@ -447,9 +460,9 @@ printf:
 	xor	rax, rax
 
 	.quit:
+	pop	r15
 	pop	r14
 	pop	r13
 	pop	r12
-	add	rsp, SIZE_QWORD
 	leave
 	ret