log: improve logging by impelementing a string formatter

The strutils now provides the `strformat` routine that can format a string
with parameters passed on the stack. Thanks to it, we can simplify other components
when it comes to logging messages.

include/strutils_h.asm

@@ -1,33 +1,42 @@
-; SPDX-FileCopyrightText: 2023 Zeal 8-bit Computer <[email protected]>
+; SPDX-FileCopyrightText: 2023-2024 Zeal 8-bit Computer <[email protected]>
 ;
 ; SPDX-License-Identifier: Apache-2.0
 
-        IFNDEF STRUTILS_H
-        DEFINE STRUTILS_H
+    IFNDEF STRUTILS_H
+    DEFINE STRUTILS_H
 
-        ; Public routines. The descriptions are given in the implementation file.
-        EXTERN strltrim
-        EXTERN strrtrim
-        EXTERN strcmp
-        EXTERN strchrnul
-        EXTERN strncmp
-        EXTERN memsep
-        EXTERN strsep
-        EXTERN strlen
-        EXTERN strcpy
-        EXTERN strcpy_unsaved
-        EXTERN strncpy
-        EXTERN strncat
-        EXTERN strtolower
-        EXTERN strtoupper
-        EXTERN parse_int
-        EXTERN parse_hex
-        EXTERN parse_dec
-        EXTERN is_print
-        EXTERN is_alpha_numeric
-        EXTERN is_digit
-        EXTERN to_lower
-        EXTERN to_upper
-        EXTERN byte_to_ascii
+    DEFC FORMAT_SPECIFIER = 0x80
+    DEFC FORMAT_SPECIFIER_MASK = 0xf
 
-        ENDIF ; STRUTILS_H
+    ; Replace with 4 characters (char array)
+    DEFC FORMAT_4_CHAR  = FORMAT_SPECIFIER | 0 | (4 << 4)
+    DEFC FORMAT_STRING  = FORMAT_SPECIFIER | 1
+    DEFC FORMAT_U8_HEX  = FORMAT_SPECIFIER | 2
+    DEFC FORMAT_CHAR    = FORMAT_SPECIFIER | 3
+
+    ; Public routines. The descriptions are given in the implementation file.
+    EXTERN strformat
+    EXTERN strltrim
+    EXTERN strcmp
+    EXTERN strchrnul
+    EXTERN strncmp
+    EXTERN memsep
+    EXTERN strsep
+    EXTERN strlen
+    EXTERN strcpy
+    EXTERN strcpy_unsaved
+    EXTERN strncpy
+    EXTERN strncat
+    EXTERN strtolower
+    EXTERN strtoupper
+    EXTERN parse_int
+    EXTERN parse_hex
+    EXTERN parse_dec
+    EXTERN is_print
+    EXTERN is_alpha_numeric
+    EXTERN is_digit
+    EXTERN to_lower
+    EXTERN to_upper
+    EXTERN byte_to_ascii
+
+    ENDIF ; STRUTILS_H

kernel/boot.asm

@@ -9,6 +9,7 @@
         INCLUDE "target_h.asm"
         INCLUDE "log_h.asm"
         INCLUDE "vfs_h.asm"
+        INCLUDE "strutils_h.asm"
 
         ; Forward declaration of symbols used below
         EXTERN zos_drivers_init
@@ -22,6 +23,7 @@
         EXTERN __KERNEL_BSS_size
         EXTERN __DRIVER_BSS_head
         EXTERN __DRIVER_BSS_size
+        EXTERN _vfs_work_buffer
 
         SECTION KERNEL_TEXT
 
@@ -86,9 +88,9 @@ zos_entry:
         call zos_time_is_available
         rrca
         jp c, _zos_boot_time_ok
-        ; Print a warning saying that we don't have any time driver
+        ; Print a warning saying that we don't have any timer driver
         ld b, a ; BC not altered by log
-        ld hl, zos_time_warning
+        ld hl, zos_timer_warning
         call zos_log_warning
         ld a, b
 _zos_boot_time_ok:
@@ -108,23 +110,21 @@ _zos_boot_date_ok:
         ld (boot_ready), a
 
         ld hl, _zos_default_init
+        ; Push on the stack in case of an error, we will need it for
+        ; the formatting string. In case of success, it will be overwritten.
+        push hl
         call zos_load_init_file
         ; If we return from zos_load_file, an error occurred
-        ld hl, _load_error_1
+        ld hl, _load_error
+        ld de, _vfs_work_buffer
+        call strformat
+        ex de, hl
         call zos_log_error
-        xor a
-        ld hl, _zos_default_init
-        call zos_log_message
-        xor a
-        ld hl, _load_error_2
-        call zos_log_message
         ; Loop until the board is rebooted
 reboot: halt
         jp reboot
 
-_load_error_1: DEFM "Could not load ", 0
-_load_error_2: DEFM " initialization file\n", 0
-
+_load_error: DEFM "Could not load ", FORMAT_STRING, " initialization file\n", 0
 
         PUBLIC _zos_default_init
 _zos_default_init:
@@ -136,12 +136,12 @@ _zos_default_init:
 zos_boilerplate:
         INCBIN "version.txt"
         DEFB "\n", 0
-zos_time_warning: DEFM "Timer unavailable\n", 0
+zos_timer_warning: DEFM "Timer unavailable\n", 0
 zos_date_warning: DEFM "Date unavailable\n", 0
 zos_kernel_ready:
         DEFM "Kernel ready.\nLoading "
         CONFIG_KERNEL_INIT_EXECUTABLE
-        DEFM "  @"
+        DEFM " @"
         STR(CONFIG_KERNEL_INIT_EXECUTABLE_ADDR)
         DEFM "\n\n", 0
 

kernel/disks.asm

@@ -17,8 +17,6 @@
         EXTERN _vfs_work_buffer
         EXTERN boot_ready
 
-        DEFC TMP_WORK_BUFFER = _vfs_work_buffer + VFS_WORK_BUFFER_SIZE / 2
-
         PUBLIC zos_disks_init
 zos_disks_init:
         ; Set the default disk to A
@@ -111,23 +109,20 @@ _zos_disks_mount_already_mounted:
         ; Alters:
         ;   A, BC, HL
 _zos_disk_print_mounter_disk:
+        push de
         ; Convert the index to an ASCII letter
         ld a, b
         add 'A'
-        ; Copy message from ROM to RAM
-        push de
-        ld de, TMP_WORK_BUFFER
+        push af
         ld hl, _mounted_msg
-        ld bc, _mounted_msg_end - _mounted_msg
-        ldir
-        ; Replace the letter in the message
-        ld (TMP_WORK_BUFFER + 5), a
-        ld hl, TMP_WORK_BUFFER
+        ld de, _vfs_work_buffer
+        call strformat
+        ex de, hl
         call zos_log_info
         pop de
         ret
 _mounted_msg:
-        DEFM "Disk ? mounted\n", 0
+        DEFM "Disk ", FORMAT_CHAR, " mounted\n", 0
 _mounted_msg_end:
     ENDIF
 

kernel/drivers.asm

@@ -21,19 +21,14 @@
 
         PUBLIC zos_drivers_init
 zos_drivers_init:
-        ; Initialize the messages, use the global usable buffer
-        ld hl, _driver_log_success
-        ld de, _vfs_work_buffer
-        ld bc, _driver_log_end - _driver_log_success
-        ldir
-
         ; Browse the driver vectors and try to initialize them all
         ld hl, __KERNEL_DRV_VECTORS_head
         ; Load the size of the vectors in B
         ; Unfortunately, we can't assert on a linker symbol
         ld b, __KERNEL_DRV_VECTORS_size / driver_end
 
 _zos_driver_init_next_driver:
+        push bc
         ; HL points to the name of the driver
         call zos_driver_name_valid     ; Check if the name is valid
         jp nc, _zos_valid_name
@@ -63,62 +58,51 @@ _zos_next_driver:
         ; Skip to the next driver in the list
         ld a, driver_end
         ADD_HL_A()
+        pop bc
         djnz _zos_driver_init_next_driver
         ; Log finished registering drivers
         ret
 
-_driver_log_success: DEFM "Driver: .... init success\n", 0
-_driver_log_failed: DEFM "Driver: .... init error $..\n", 0
+_driver_log_success: DEFM "Driver: ", FORMAT_4_CHAR , " init success\n", 0
+_driver_log_failed:  DEFM "Driver: ", FORMAT_4_CHAR , " init error $", FORMAT_U8_HEX ,"\n", 0
 _driver_log_end:
 
-        DEFC SUCCESS_MESSAGE_LEN = _driver_log_failed - _driver_log_success
-        DEFC FAILED_MESSAGE_LEN = _driver_log_end - _driver_log_failed
-        DEFC LOG_MESSAGES_LEN = FAILED_MESSAGE_LEN + SUCCESS_MESSAGE_LEN
-        ASSERT(VFS_WORK_BUFFER_SIZE >= SUCCESS_MESSAGE_LEN + FAILED_MESSAGE_LEN)
-
         ; Copies the driver name and the error to the log buffer.
         ; Then calls the error log function.
         ; Parameters:
         ;       HL - Driver name (4 characters)
+        ;       DE - Temporary buffer
         ;       A - Error code
         ; Alters:
         ;       A, C, DE
 _zos_driver_log_error:
-        ; Setting C to DRIVER_NAME_LENGTH will prevent any modification
-        ; on B when performing ldir
-        ld c, DRIVER_NAME_LENGTH
+        ; HL must not be altered
         push hl
-        ; Point to the log failed message
-        ld de, _vfs_work_buffer + SUCCESS_MESSAGE_LEN + 8
-        REPT DRIVER_NAME_LENGTH
-        ldi
-        ENDR
-        ; Point to failed log message's error code
-        ld hl, _vfs_work_buffer + LOG_MESSAGES_LEN - 4
-        call byte_to_ascii
-        ld (hl), d
-        inc hl
-        ld (hl), e
-        ld hl, _vfs_work_buffer + SUCCESS_MESSAGE_LEN
+        ; Push the error code on the stack for the format string
+        push af
+        push hl
+        ; REPT DRIVER_NAME_LENGTH
+        ld hl, _driver_log_failed
+        ; Prepare the temporary buffer in DE
+        ld de, _vfs_work_buffer
+        call strformat
+        ex de, hl
         call zos_log_error
         pop hl
         ret
         ; Same as above but with a success
 _zos_driver_log_success:
-        ; Setting C to DRIVER_NAME_LENGTH will prevent any modification
-        ; on B when performing ldir
-        ld c, DRIVER_NAME_LENGTH
+        ; HL must not be altered
         push hl
-        ; Point to the log failed message
-        ld de, _vfs_work_buffer + 8
-        REPT DRIVER_NAME_LENGTH
-        ldi
-        ENDR
-        ld hl, _vfs_work_buffer
+        push hl
+        ld hl, _driver_log_success
+        ld de, _vfs_work_buffer
+        call strformat
+        ; Put the message to print in DE, as required by zos_log_info
+        ex de, hl
         call zos_log_info
+        xor a
         pop hl
-        ; Do not alter former flags
-        or a
         ret
 
         ; Checks whether the name has already been registered
@@ -128,7 +112,7 @@ _zos_driver_log_success:
         ;       A  - 0 if exists, non-zero else
         ;       DE - Address of the existing drivers (if any)
         ; Alters:
-        ;       A, DE, C
+        ;       A, DE, BC
         PUBLIC zos_driver_find_by_name
 zos_driver_find_by_name:
         ; If we have no drivers, returns 1 directly
@@ -152,7 +136,6 @@ zos_driver_find_by_name:
         ; B must not be altered, but C can be altered
         jp zos_disks_get_driver_and_fs
 _zos_driver_find_by_name_driver:
-        push bc
         ; Save HL as it must not be destroyed
         push hl
         ; Calculate the offset in the loaded drivers array
@@ -185,7 +168,6 @@ _zos_driver_find_by_name_loop:
         inc a   ; return A strictly positive
 _zos_driver_find_by_name_already_exists:
         pop hl
-        pop bc
         ret
 _zos_driver_failure:
         ld a, ERR_INVALID_NAME
@@ -233,15 +215,14 @@ zos_driver_name_valid:
         ; Returns:
         ;       A - 0 on success, error code else
         ; Alters:
-        ;       A, DE
+        ;       A, BC, DE
 zos_driver_register:
         ; Check if we can still register a driver
         ld a, (_loaded_drivers_count)
         cp CONFIG_KERNEL_MAX_LOADED_DRIVERS
         jr z, _zos_driver_register_full
         ; Call the driver's init function first
-        ; Save HL and BC as we need them in the caller
-        push bc
+        ; Save HL as we need it in the caller
         push hl
         ; Optimize a bit
         ASSERT(driver_init_t == 4)
@@ -257,7 +238,6 @@ zos_driver_register:
         ; Perform a call to a register address (HL)
         CALL_HL()
         pop hl
-        pop bc
         ; If it succeeded but is hidden, return (but as a success)
         ASSERT(ERR_DRIVER_HIDDEN == 255)
         inc a