More generic macros for specific encodings

edlin.asm

@@ -21,29 +21,39 @@ sys_set_dta equ 0x1a
 sys_block_read equ 0x27
 
 ; Special instruction encodings
-%macro add_cx_ax 0
-	db 0x03, 0xC8 ; add cx, ax (direction swapped)
-%endmacro
-%macro add_di_cx 0
-	db 0x03, 0xF9 ; 023E add di, cx (direction swapped)
-%endmacro
+%define r_ax 0
+%define r_cx 1
+%define r_dx 2
+%define r_bx 3
+%define r_sp 4
+%define r_bp 5
+%define r_si 6
+%define r_di 7
 
-%macro or_al_al 0
-	db 0x0a, 0xc0 ; or al, al (direction swapped)
-%endmacro
+%define r_al 0
+%define r_cl 1
+%define r_dl 2
+%define r_bl 3
+%define r_ah 4
+%define r_ch 5
+%define r_dh 6
+%define r_bh 7
 
-%macro xor_ax_ax 0
-	db 0x33, 0xc0 ; xor ax, ax (direction swapped)
+; Direction swapped reg, reg
+%macro addw 2
+	db 0x03, 0xc0 + 8 * %1 + %2
 %endmacro
-
-%macro mov_ax_cx 0
-	db 0x8b, 0xc1 ; mov ax, cx (direction swapped)
+%macro orb 2
+	db 0x0a, 0xc0 + 8 * %1 + %2
 %endmacro
-%macro mov_dx_cx 0
-	db 0x8b, 0xD1 ; mov dx, cx (direction swapped)
+%macro subw 2
+	db 0x2b, 0xc0 + 8 * %1 + %2
 %endmacro
-%macro mov_di_dx 0
-	db 0x8B, 0xfa ; mov di, dx (direction swapped)
+%macro xorw 2
+	db 0x33, 0xc0 + 8 * %1 + %2
+%endmacro
+%macro movw 2
+	db 0x8b, 0xc0 + 8 * %1 + %2
 %endmacro
 
 %macro cmp_byteaddr_bytext 2
@@ -77,7 +87,7 @@ ensure_file_argument:
 	je print_filename_missing_error
 
 	; AL at program start a flag of whether drive specifier in first parameter valid
-	or_al_al
+	orb r_al, r_al
 	mov dx, invalid_name_error
 	jnz _trampoline_error_1
 
@@ -93,7 +103,7 @@ open_file:
 	int 0x21
 
 	mov [new_file_flag], al
-	or_al_al
+	orb r_al, r_al
 	jz delete_old_bak
 
 	mov dx, new_file_str
@@ -123,7 +133,7 @@ delete_old_bak: ; 01b9
 
 	mov ah, sys_create_file
 	int 0x21
-	or_al_al
+	orb r_al, r_al
 	jz setup_file_parameters
 
 	mov dx, directory_full_error
@@ -134,7 +144,7 @@ print_bak_error: ; 01e6
 	jmp error
 
 setup_file_parameters: ; 01ec
-	xor_ax_ax
+	xorw r_ax, r_ax
 	mov [psp_fcb_1 + fcb_record_low], ax
 	mov [psp_fcb_1 + fcb_record_high], ax
 	mov [__0a58_fcb + fcb_record_low], ax
@@ -145,7 +155,7 @@ setup_file_parameters: ; 01ec
 	mov [__0a58_fcb + fcb_record_size], ax
 
 	mov dx, disk_transfer_area
-	mov_di_dx
+	movw r_di, r_dx
 	mov ah, sys_set_dta
 	int 0x21
 
@@ -161,13 +171,13 @@ setup_file_parameters: ; 01ec
 
 	; __0a94 = ¼ available memory
 	shr cx, 1
-	mov_ax_cx
+	movw r_ax, r_cx
 	shr cx, 1
 	mov [__0a94], cx
 	; cx = ¾ available memory
-	add_cx_ax
+	addw r_cx, r_ax
 
-	mov_dx_cx
+	movw r_dx, r_cx
 	add dx, disk_transfer_area
 	mov [__0a96], dx
 
@@ -175,8 +185,8 @@ read_file:
 	mov dx, psp_fcb_1
 	mov ah, sys_block_read
 	int 0x21
-	call __035e
-	add_di_cx
+	call find_file_end_char
+	addw r_di, r_cx
 
 __0240:
 db 0xFC ; 0240 cld
@@ -300,18 +310,22 @@ db 0x17 ; 035A pop ss
 db 0x04, 0xA6 ; 035B add al,0xa6
 db 0x08 ; 035D db 0x08
 
-__035e:
-db 0x57 ; 035E push di
-db 0x51 ; 035F push cx
-db 0xB0, 0x1A ; 0360 mov al,0x1a
-db 0xF2, 0xAE ; 0362 repne scasb
-db 0x8B, 0xF9 ; 0364 mov di,cx
-db 0x59 ; 0366 pop cx
-db 0x9F ; 0367 lahf
-db 0x2B, 0xCF ; 0368 sub cx,di
-db 0x9E ; 036A sahf
-db 0x5F ; 036B pop di
-db 0xC3 ; 036C ret
+find_file_end_char: ; 035e
+	push di
+	push cx
+
+	mov al, 0x1a ; ^Z
+	repne scasb
+	movw r_di, r_cx
+
+	pop cx
+	lahf
+	subw r_cx, r_di
+	sahf
+
+	pop di
+	ret
+
 db 0xE9, 0x8E, 0x00 ; 036D jmp 0x3fe
 db 0xF6, 0x06, 0x7E, 0x0A, 0xFF ; 0370 test byte [0xa7e],0xff
 db 0x75, 0xF6 ; 0375 jnz 0x36d