From 5724456ec493a847981266c51d7ccd73cbb15aea Mon Sep 17 00:00:00 2001 From: Ben Pfaff Date: Tue, 17 Aug 2004 06:35:16 +0000 Subject: [PATCH] Wait for DRQ in status register to transition low before reading sector. --- src/threads/loader.S | 23 +++++++++++++++++++---- 1 file changed, 19 insertions(+), 4 deletions(-) diff --git a/src/threads/loader.S b/src/threads/loader.S index f2563bb..18086ed 100644 --- a/src/threads/loader.S +++ b/src/threads/loader.S @@ -78,38 +78,53 @@ protcseg: movl $1, %ebx movl $0x100000, %edi -read_sector: +read_sector: + + ### Poll status register while controller busy. movl $0x1f7, %edx 1: inb %dx, %al testb $0x80, %al jnz 1b - + + ### Read a single sector. movl $0x1f2, %edx movb $1, %al outb %al, %dx + ### Sector number to write in low 28 bits. + ### LBA mode, device 0 in top 4 bits. movl %ebx, %eax andl $0x0fffffff, %eax orl $0xe0000000, %eax + ### Dump %eax to ports 0x1f3...0x1f6. movl $4, %ecx -2: incl %edx +2: incw %dx outb %al, %dx shrl $8, %eax loop 2b + ### READ command to command register. incw %dx movb $0x20, %al outb %al, %dx - + + ### Poll status register while controller busy. 1: inb %dx, %al testb $0x80, %al jnz 1b + ### Poll status register until data ready. +1: inb %dx, %al + testb $0x08, %al + jz 1b + + ### Transfer sector. movl $512 / 4, %ecx movl $0x1f0, %edx rep insl + ### Next sector. incl %ebx cmpl $KERNEL_LOAD_PAGES*8 + 1, %ebx jnz read_sector -- 2.30.2