fixed partial loading bug

[bootcensus] / src / boot / boot.s

diff --git a/src/boot/boot.s b/src/boot/boot.s
index 8ba4a11..b9e1a76 100644 (file)
--- a/src/boot/boot.s
+++ b/src/boot/boot.s
@@ -1,12 +1,15 @@
        .code16
        .section .boot,"a"
 
+       .set scratchbuf, 0x7b00
+
+boot:
        cli
        cld
        # move stack to just below the code
        xor %ax, %ax
        mov %ax, %ss
-       mov $0x7c00, %sp
+       mov $0x7b00, %sp
        # use the code segment for data access
        mov %cs, %ax
        mov %ax, %ds
@@ -16,9 +19,6 @@
 
        call setup_serial
 
-       mov $_boot2_size, %eax
-       call print_num
-
        # load the second stage boot loader and jump to it
        mov $_boot2_size, %eax
        mov %eax, %ebx
@@ -37,9 +37,6 @@
        call read_sectors
        jmp boot2_addr
 
-       cli
-       hlt
-
        .set SECT_PER_TRACK, 18
 
        .set ARG_NSECT, 6
@@ -66,10 +63,7 @@ read_sectors:
        ret
 
        .set VAR_ATTEMPTS, -2
-str_rdsec_msg: .asciz "rdsec: "
-str_cyl_msg: .asciz " C "
-str_head_msg: .asciz " H "
-str_sec_msg: .asciz " S "
+#str_rdsec_msg: .asciz "rdsec: "
 
 # read_sector(sidx)
 read_sector:
@@ -84,8 +78,8 @@ read_sector:
 .Lread_try:
        # calculate the track (sidx / sectors_per_track)
        mov 4(%bp), %ax
-       mov $str_rdsec_msg, %si
-       call print_str_num16
+#      mov $str_rdsec_msg, %si
+#      call print_str_num16
 
        xor %dx, %dx
        mov $SECT_PER_TRACK, %cx
@@ -104,23 +98,6 @@ read_sector:
        inc %al
        or %al, %cl
 
-       mov $str_cyl_msg, %si
-       mov %cx, %ax
-       rol $2, %al
-       and $3, %al
-       ror $8, %ax
-       call print_str_num16
-
-       mov $str_head_msg, %si
-       xor %ax, %ax
-       mov %dh, %al
-       call print_str_num16
-
-       mov $str_sec_msg, %si
-       mov %cl, %al
-       and $0x3f, %ax
-       call print_str_num16
-
        # ah = 2 (read), al = 1 sectors
        mov $0x0201, %ax
        movb drive_number, %dl
@@ -141,9 +118,14 @@ read_sector:
        jmp abort_read
 
 .Lread_ok:
+       # DBG print first dword
+#      mov $str_read_error + 4, %si
+#      mov %es:(%bx), %eax
+#      call print_str_num
+
        # increment es:bx accordingly (advance es if bx overflows)
        add $512, %bx
-       jno 0f
+       jnc 0f
        mov %es, %ax
        add $4096, %ax
        mov %ax, %es
@@ -154,12 +136,11 @@ read_sector:
        pop %bp
        ret
 
-str_read_error: .asciz "err read sector: "
+str_read_error: .asciz "err read sect: "
 
 abort_read:
        mov $str_read_error, %si
        call print_str_num16
-       cli
        hlt
 
 cursor_x: .byte 0
@@ -170,6 +151,8 @@ print_str_num:
        call print_str
        pop %eax
        call print_num
+       mov $13, %al
+       call ser_putchar
        mov $10, %al
        call ser_putchar
        ret
@@ -210,13 +193,14 @@ print_str:
        ret
 
        # expects number in eax
+       .global print_num
 print_num:
        # save registers
        push %es
        pusha
 
        xor %cx, %cx
-       movw $numbuf, %si
+       movw $scratchbuf, %si
        mov $10, %ebx
 
 0:     xor %edx, %edx
@@ -300,6 +284,7 @@ setup_serial:
        ret
 
        # expects a character in al
+       .global ser_putchar
 ser_putchar:
        push %dx
 
@@ -328,7 +313,6 @@ ser_putstr:
        
 
 drive_number: .byte 0
-numbuf: .space 8
        .org 510
        .byte 0x55
        .byte 0xaa