second stage boot loader now loads the main program

[bootcensus] / src / boot / boot.s

diff --git a/src/boot/boot.s b/src/boot/boot.s
index 04f928e..50817a3 100644 (file)
--- a/src/boot/boot.s
+++ b/src/boot/boot.s
@@ -7,7 +7,7 @@
 # (at your option) any later version.
 # 
 # This program is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# but WITHOUT ANY WARRANTY, without even the implied warranty of
 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 # GNU General Public License for more details.
 # 
@@ -15,7 +15,7 @@
 # along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
        .code16
-       .section .boot,"a"
+       .section .boot,"ax"
 
        .set stack_top, 0x7be0
        .set read_retries, 0x7be8
@@ -48,6 +48,7 @@ boot:
        mov $_boot2_size, %eax
        call print_num
 
+       mov $_boot2_size, %eax
        mov %eax, %ebx
        shr $9, %eax
        and $0x1ff, %ebx
@@ -64,15 +65,16 @@ boot:
        call read_sectors
        jmp boot2_addr
 
-       .set ARG_NSECT, 6
-       .set ARG_SIDX, 4
-
 loading_msg: .asciz "\nLoad "
-driveno_msg: .asciz "Drive: "
+driveno_msg: .asciz "Drv:"
 
+       .global sect_per_track
 sect_per_track: .short 18
+       .global num_cylinders
 num_cylinders: .short 80
+       .global num_heads
 num_heads: .short 2
+       .global heads_mask
 heads_mask: .byte 1
 
 get_drive_chs:
@@ -87,10 +89,10 @@ get_drive_chs:
 
        mov $8, %ah
        int $0x13
-       jnc .Lok
+       jnc ok
        ret
 
-.Lok:  xor %eax, %eax
+ok:    xor %eax, %eax
        mov %ch, %al
        mov %cl, %ah
        rol $2, %ah
@@ -117,6 +119,10 @@ get_drive_chs:
        call print_num
        ret
 
+
+       .set ARG_NSECT, 6
+       .set ARG_SIDX, 4
+
 # read_sectors(first, num)
 read_sectors:
        push %bp
@@ -146,7 +152,7 @@ read_sector:
 
        movw $3, read_retries
 
-.Lread_try:
+read_try:
        # calculate the track (sidx / sectors_per_track)
        mov 4(%bp), %ax
 
@@ -178,22 +184,22 @@ read_sector:
        mov $0x0201, %ax
        movb drive_number, %dl
        int $0x13
-       jnc .Lread_ok
+       jnc read_ok
 
        # abort after 3 attempts
        decw read_retries
-       jz .Lread_fail
+       jz read_fail
 
        # error detected, reset controller and retry
        xor %ah, %ah
        int $0x13
-       jmp .Lread_try
+       jmp read_try
 
-.Lread_fail:
+read_fail:
        mov 4(%bp), %ax
        jmp abort_read
 
-.Lread_ok:
+read_ok:
        mov $46, %ax
        call print_char
 
@@ -209,7 +215,7 @@ read_sector:
        pop %bp
        ret
 
-str_read_error: .asciz "rderr: "
+str_read_error: .asciz "rderr:"
 
 abort_read:
        mov $str_read_error, %si
@@ -226,18 +232,24 @@ print_str:
 
 0:     mov (%si), %al
        cmp $0, %al
-       jz .Lend
+       jz end
        call print_char
        inc %si
        jmp 0b
 
-.Lend: popa
+end:   popa
        ret
 
        # expects character in al
 print_char:
        push %es
-       pushw $0xb800
+
+       push %ax
+       cmp $10, %ax
+       jnz 0f
+       mov $32, %ax
+
+0:     pushw $0xb800
        pop %es
        movw cursor_x, %di
        shl $1, %di
@@ -246,6 +258,7 @@ print_char:
        movb $7, %es:1(%di)
        incw cursor_x
 
+       pop %ax
        call ser_putchar
        pop %es
        ret
@@ -259,14 +272,14 @@ print_num:
        movw $scratchbuf + scratchbuf_size, %si
        movb $0, (%si)
        mov $10, %ebx
-.Lconvloop:
+convloop:
        xor %edx, %edx
        div %ebx
        add $48, %dl
        dec %si
        mov %dl, (%si)
        cmp $0, %eax
-       jnz .Lconvloop
+       jnz convloop
 
        call print_str
 
@@ -284,12 +297,8 @@ print_num:
        .set DIV_9600, 115200 / 9600
        .set LCTL_8N1, 0x03
        .set LCTL_DLAB, 0x80
-       .set FIFO_ENABLE, 0x01
-       .set FIFO_SEND_CLEAR, 0x04
-       .set FIFO_RECV_CLEAR, 0x02
-       .set MCTL_DTR, 0x01
-       .set MCTL_RTS, 0x02
-       .set MCTL_OUT2, 0x08
+       .set FIFO_ENABLE_CLEAR, 0x07
+       .set MCTL_DTR_RTS_OUT2, 0x0b
        .set LST_TREG_EMPTY, 0x20
 
 setup_serial:
@@ -308,21 +317,16 @@ setup_serial:
        mov $UART_LCTL, %dx
        out %al, %dx
        # clear and enable fifo
-       mov $FIFO_ENABLE, %al
-       or $FIFO_SEND_CLEAR, %al
-       or $FIFO_RECV_CLEAR, %al
+       mov $FIFO_ENABLE_CLEAR, %al
        mov $UART_FIFO, %dx
        out %al, %dx
        # assert RTS and DTR
-       mov $MCTL_DTR, %al
-       or $MCTL_RTS, %al
-       or $MCTL_OUT2, %al
+       mov $MCTL_DTR_RTS_OUT2, %al
        mov $UART_MCTL, %dx
        out %al, %dx
        ret
 
        # expects a character in al
-       .global ser_putchar
 ser_putchar:
        push %dx
 
@@ -336,9 +340,9 @@ ser_putchar:
 0:     mov %al, %ah
        # wait until the transmit register is empty
        mov $UART_LSTAT, %dx
-.Lwait:        in %dx, %al
+wait:  in %dx, %al
        and $LST_TREG_EMPTY, %al
-       jz .Lwait
+       jz wait
        mov $UART_DATA, %dx
        mov %ah, %al
        out %al, %dx