diff options
Diffstat (limited to 'stand/i386/boot0/Makefile')
| -rw-r--r-- | stand/i386/boot0/Makefile | 19 |
1 files changed, 13 insertions, 6 deletions
diff --git a/stand/i386/boot0/Makefile b/stand/i386/boot0/Makefile index 82eb9eefee76..bfd566dfa45c 100644 --- a/stand/i386/boot0/Makefile +++ b/stand/i386/boot0/Makefile @@ -1,4 +1,3 @@ -# $FreeBSD$ PROG?= boot0 STRIP= @@ -36,19 +35,27 @@ BOOT_BOOT0_FLAGS?= 0x8f # 0xb6 (182d) corresponds to 10 seconds. BOOT_BOOT0_TICKS?= 0xb6 -# The base address that we the boot0 code to to run it. Don't change this -# unless you are glutton for punishment. -BOOT_BOOT0_ORG?= 0x600 -ORG=${BOOT_BOOT0_ORG} +# The BIOS loads boot0 to the hardcoded address 0x7c00. boot0 copies +# itself to this alternate base address before continuing execution so +# that next level boot blocks can be loaded at the 0x7c00 address they +# expect. +ORG= 0x600 # Comm settings for boot0sio. +# +# boot0sio uses BIOS INT $0x14 for serial ports, we can only support these +# baudrates due to INT14's limited interface. In addition, if +# BOOT_BOOT0_COMCONSOLE_SPEED=0, then the baud rate and frame format will remain +# unchanged. Some BIOSes initialize the serial ports to 115200, and this may +# allow boot0sio access at that rate if so. +# # Bit(s) Description # 7-5 data rate (110,150,300,600,1200,2400,4800,9600 bps) # 4-3 parity (00 or 10 = none, 01 = odd, 11 = even) # 2 stop bits (set = 2, clear = 1) # 1-0 data bits (00 = 5, 01 = 6, 10 = 7, 11 = 8) .if !defined(BOOT_BOOT0_COMCONSOLE_SPEED) -BOOT_COMCONSOLE_SPEED?= 9600 +BOOT_COMCONSOLE_SPEED?= 9600 # BIOS interfaces do not support higher rates. .if ${BOOT_COMCONSOLE_SPEED} == 9600 BOOT_BOOT0_COMCONSOLE_SPEED= "7 << 5 + 3" .elif ${BOOT_COMCONSOLE_SPEED} == 4800 |