Adds format(), modified __INTERNAL_fmt to allow writing to memory (instead of writing to given FD)

2025-07-31 14:18:00 +02:00
parent c36ae377ba
commit 00568e2e7c
2 changed files with 112 additions and 29 deletions
--- a/src/console.asm
+++ b/src/console.asm
@@ -1,6 +1,7 @@
 %include "src/constants.asm"

 extern	strlen
+extern	strcat
 extern	itoa
 extern	utoa

@@ -88,6 +89,7 @@ puts:
 ;	\t	Tab
 ; Used registers:
 ;	rax*	(ret) amount of printed characters
+;	rbx	Length of array being written to (if rax != FD)
 ;	rdi*	(arg) pointer to format[] to format and print >> pointer to buffer
 ;	rsi*	(optional arg) >> Used for inserting strings to buffer
 ;	rdx*	(optional arg) >> misc
@@ -181,7 +183,32 @@ __INTERNAL_fmt:
 	jmp	.insertString
 	%endmacro

+	%macro check_formatted_len 2 ;check_format_len [return_label] [offset]
+	test	rbx, rbx
+	jz	%%checkBufferLen
+	cmp	r11, rbx
+	jae	.wrapup
+	jmp	.flushReturn_%1
+	%%checkBufferLen:
+	mov	r9b, %1
+	cmp	r10, __fmt_BuffLen-%2
+	je	.flushBuffer
+	.flushReturn_%1:
+	%endmacro
+
+	%macro write_format_data 3 ;write_format_data [size] [offset] [what]
+	test	rbx, rbx
+	jz	%%writeToBuffer
+	mov	%1 [r15 + %2], %3
+	jmp	%%cnt
+	%%writeToBuffer:
+	mov	%1 [__fmt_Buff + %2], %3
+	%%cnt:
+	%endmacro
+
 	; entry:
+	test	rax, rax
+	js	.start_fmt ;jump if signed; FD => Mem
 	cmp	rax, 0
 	jg	.start_fmt
 	mov	rax, -EBADF
@@ -189,12 +216,20 @@ __INTERNAL_fmt:
 	.start_fmt:
 	push	rbp
 	mov	rbp, rsp
+	sub	rsp, SIZE_QWORD
+	push	rbx
 	push	r12
 	push	r13
 	push	r14
 	push	r15
 	mov	r15, rax
+	xor	rbx, rbx
+	test	r15, r15
+	jns	.checkEmptyStr
+	not	r15
+	mov	rbx, [rbp + RBP_OFFSET_CALLER]

+	.checkEmptyStr:
 	cmp	byte [rdi], EOS
 	je	.emptyStr

@@ -213,16 +248,13 @@ __INTERNAL_fmt:
 	.process:
 		cmp	byte [rdi], EOS
 		je	.wrapup
-		xor	r9b, r9b
-		cmp	r10, __fmt_BuffLen-1
-		je	.flushBuffer
-		.flushReturn_0:
+			check_formatted_len 0,1
 		cmp	byte [rdi], '\'
 		je	.asciiReplacement
 		cmp	byte [rdi], '%'
 		je	.argReplacement
 		mov	r8b, [rdi]
-		mov	[__fmt_Buff+r10], r8b
+			write_format_data byte,r10,r8b
 		inc	r10
 		inc	r11
 		inc	rdi
@@ -240,15 +272,10 @@ __INTERNAL_fmt:
 		cmp	byte [rdi + 1], 't'
 		cmove	r9, r8
 		je	.replaceAscii
-
 		jmp	.invalidReplacement
 		.replaceAscii:
-		mov	r8b, r9b
-		mov	r9b, 2
-		cmp	r10, __fmt_BuffLen-1
-		je	.flushBuffer
-		.flushReturn_2:
-		mov	[__fmt_Buff + r10], r8b
+			check_formatted_len 1, 1
+			write_format_data byte,r10,r8b
 		add	rdi, 2
 		inc	r10
 		inc	r11
@@ -342,7 +369,7 @@ __INTERNAL_fmt:
 		cmp	byte [rdi + 1], '\'
 		je	.invalidReplacement_specialChar; '%\n' would become "'%','\','n'" instead of "'%',EOS" when inserting full invalid specifier.
 		mov	r9w, word [rdi]
-		mov	[__fmt_Buff+r10], r9w
+			write_format_data word,r10,r9w
 		add	rdi, 2
 		add	r10, 2
 		add	r11, 2
@@ -350,7 +377,7 @@ __INTERNAL_fmt:
 		jmp	.process
 		.invalidReplacement_specialChar:
 		mov	r9b, byte [rdi]
-		mov	[__fmt_Buff+r10], r9b
+			write_format_data byte,r10,r9b
 		inc	rdi
 		inc	r10
 		inc	r11
@@ -405,14 +432,10 @@ __INTERNAL_fmt:
 		.insertString:
 			test	rsi, rsi
 			jnz	.doInsertString
-			;rsi = NULL:
-			mov	r9b, 3
-			cmp	r10, __fmt_BuffLen-7
-			je	.flushBuffer
-			.flushReturn_3:
-			mov	byte [__fmt_Buff + r10], '('
-			mov	qword [__fmt_Buff + r10 + 1], 'null'
-			mov	byte [__fmt_Buff + r10 + 5], ')'
+				check_formatted_len 2, 7
+				write_format_data byte,r10,'('
+				write_format_data qword,r10+1,'null'
+				write_format_data byte,r10+5,')'
 			add	r10, 6
 			add	r11, 6
 			jmp	.endInsertString
@@ -420,12 +443,9 @@ __INTERNAL_fmt:
 			.doInsertString:
 			cmp	byte [rsi], EOS
 			je	.endInsertString
-			mov	r9b, 1
-			cmp	r10, __fmt_BuffLen-1
-			je	.flushBuffer
-			.flushReturn_1:
+				check_formatted_len 3, 1
 			mov	r8b, byte [rsi]
-			mov	[__fmt_Buff + r10], r8b
+				write_format_data byte,r10,r8b
 			inc	rsi
 			inc	r10
 			inc	r11
@@ -438,7 +458,7 @@ __INTERNAL_fmt:

 		;--- Insert char to buffer ---;
 		.insertChar:
-		mov	[__fmt_Buff + r10], sil
+			write_format_data byte,r10,sil
 		add	rdi, 2
 		add	r10, 1
 		add	r11, 1
@@ -447,6 +467,22 @@ __INTERNAL_fmt:
 		jmp	.process

 	.flushBuffer:
+	test	rbx, rbx
+	jz	.flush_print
+	sub	rsp, SIZE_QWORD
+	push	rdi
+	push	rsi
+	push	rdx
+	lea	rdi, [r15]
+	lea	rsi, [rel __fmt_Buff]
+	mov	rdx, rbx
+	call	strcat
+	pop	rdx
+	pop	rsi
+	pop	rdi
+	add	rsp, SIZE_QWORD
+	jmp	.flush_ret
+	.flush_print:
 	push	rdi
 	push	rsi
 	push	rdx
@@ -463,7 +499,7 @@ __INTERNAL_fmt:
 	test	rax, rax
 	js	.quit
 	xor	r10, r10
-
+	.flush_ret:
 	cmp	r9b, 0
 	je	.flushReturn_0
 	cmp	r9b, 1
@@ -474,6 +510,19 @@ __INTERNAL_fmt:
 	je	.flushReturn_3

 	.wrapup:
+	test	rbx, rbx
+	jz	.wrapup_print
+	mov	byte [r15+r10+1], EOS
+	lea	rdi, [r15]
+	lea	rsi, [rel __fmt_Buff]
+	mov	rdx, rbx
+	sub	rsp, SIZE_QWORD
+	push	r11
+	call	strcat
+	pop	rax
+	add	rsp, SIZE_QWORD
+	jmp	.quit
+	.wrapup_print:
 	mov	rax, NR_write
 	mov	rdi, r15
 	lea	rsi, [rel __fmt_Buff]
@@ -493,6 +542,8 @@ __INTERNAL_fmt:
 	pop	r14
 	pop	r13
 	pop	r12
+	pop	rbx
+	add	rsp, SIZE_QWORD
 	leave
 	ret

--- a/src/string.asm
+++ b/src/string.asm
@@ -1,5 +1,7 @@
 %include "src/constants.asm"

+extern	__INTERNAL_fmt
+
 section .text
 	global	strlen
 	global	strcpy
@@ -7,6 +9,7 @@ section .text
 	global	strclr
 	global	strcmp
 	global	strfind
+	global	format

 ;----- strlen(*str[]) -----;
 ; Gets the length of given string
@@ -216,3 +219,32 @@ strfind:
 	mov	rax, r8
 	.quit:
 	ret
+
+;----- format(*dest[], len, *fmt[], ...) -----;
+; Formats a string and writes it to memory.
+; See __INTERNAL_fmt for valid specifiers
+; Return value: Amount of characters written to dest[]
+; Used registers:
+;	rax*	(ret)
+;	rdi*	(arg) Pointer to dest[]
+;	rsi*	(arg) Size of dest[]
+;	rdx*	(arg) Pointer to fmt[]
+format:
+	push	rbp
+	mov	rbp, rsp
+
+	mov	rax, rdi
+	not	rax ;__INTERNAL_fmt; ~FD => Mem
+	sub	rsp, SIZE_QWORD
+	push	rsi ;__INTERNAL_fmt: pop len from stack if rax is signed
+	lea	rdi, [rdx]
+	mov	rsi, rcx
+	mov	rdx, r8
+	mov	rcx, r9
+	mov	r8, [rbp + RBP_OFFSET_CALLER + SIZE_QWORD * 0]
+	mov	r9, [rbp + RBP_OFFSET_CALLER + SIZE_QWORD * 1]
+	call	__INTERNAL_fmt
+	add	rsp, SIZE_QWORD * 2
+
+	leave
+	ret