tftf/framework/aarch32/asm_debug.S

/*
 * Copyright (c) 2018, Arm Limited. All rights reserved.
 *
 * SPDX-License-Identifier: BSD-3-Clause
 */

#include <arch.h>
#include <asm_macros.S>

#if ENABLE_ASSERTIONS

	.globl	asm_assert

/* Since the max decimal input number is 65536 */
#define MAX_DEC_DIVISOR		10000

/* The offset to add to get ascii for numerals '0 - 9' */
#define ASCII_OFFSET_NUM	'0'

.section .rodata.assert_str, "aS"
assert_msg1:
	.asciz "ASSERT: File "
assert_msg2:
	.asciz " Line "

/* ---------------------------------------------------------------------------
 * Assertion support in assembly.
 * The below function helps to support assertions in assembly where we do not
 * have a C runtime stack. Arguments to the function are :
 * r0 - File name
 * r1 - Line no
 * Clobber list : lr, r0 - r6
 * ---------------------------------------------------------------------------
 */
func asm_assert
	/*
	 * Only print the output if LOG_LEVEL is higher or equal to
	 * LOG_LEVEL_INFO, which is the default value for builds with DEBUG=1.
	 */
	/* Stash the parameters already in r0 and r1 */
	mov	r5, r0
	mov	r6, r1

	/* Initialize crash console and verify success */
	bl	plat_crash_console_init
	cmp	r0, #0
	beq	1f

	/* Print file name */
	ldr	r4, =assert_msg1
	bl	asm_print_str
	mov	r4, r5
	bl	asm_print_str

	/* Print line number string */
	ldr	r4, =assert_msg2
	bl	asm_print_str

	/* Test for maximum supported line number */
	ldr	r4, =~0xffff
	tst	r6, r4
	bne	1f
	mov	r4, r6

	/* Print line number in decimal */
	mov	r6, #10			/* Divide by 10 after every loop iteration */
	ldr	r5, =MAX_DEC_DIVISOR
dec_print_loop:
	udiv	r0, r4, r5			/* Quotient */
	mls	r4, r0, r5, r4			/* Remainder */
	add	r0, r0, #ASCII_OFFSET_NUM	/* Convert to ASCII */
	bl	plat_crash_console_putc
	udiv	r5, r5, r6			/* Reduce divisor */
	cmp	r5, #0
	bne	dec_print_loop

	bl	plat_crash_console_flush

1:
	wfi
	b	1b
endfunc asm_assert

/*
 * This function prints a string from address in r4
 * Clobber: lr, r0 - r4
 */
func asm_print_str
	mov	r3, lr
1:
	ldrb	r0, [r4], #0x1
	cmp	r0, #0
	beq	2f
	bl	plat_crash_console_putc
	b	1b
2:
	bx	r3
endfunc asm_print_str

/*
 * This function prints a hexadecimal number in r4.
 * In: r4 = the hexadecimal to print.
 * Clobber: lr, r0 - r3, r5
 */
func asm_print_hex
	mov	r3, lr
	mov	r5, #32  /* No of bits to convert to ascii */
1:
	sub	r5, r5, #4
	lsr	r0, r4, r5
	and	r0, r0, #0xf
	cmp	r0, #0xa
	blo	2f
	/* Add by 0x27 in addition to ASCII_OFFSET_NUM
	 * to get ascii for characters 'a - f'.
	 */
	add	r0, r0, #0x27
2:
	add	r0, r0, #ASCII_OFFSET_NUM
	bl	plat_crash_console_putc
	cmp	r5, #0
	bne	1b
	bx	r3
endfunc asm_print_hex

#endif /* ENABLE_ASSERTIONS */