Zipit Z1
BootROM程式
程式碼如下：
Hw_UARTDR1 equ 0x480 Hw_UBRLCR1 equ 0x4c0 Hw_BR9600 equ 0x17 Hw_BR9600_13 equ 0x0b Hw_WRDLEN8 equ 0x60000 StartFlag equ '>' EndFlag equ '>' uart_boot_base: mov r12, #HwRegisterBase @ r12 = 0x80000000 mov r8, #InternalRamBase @ r8 = 0x10000000 add r9, r8, #ImageSize @ r9 = 0x10000800 @ first, initialize hw control of uart mov r0, #Hw_UART1EN @enable uart str r0, [r12, #Hw_SYSCON] add r1, r12, #Hw_SYSFLG2 ldr r7, [r1] @ r7 = SYSFLG2 tst r7, #Hw_CKMODE movne r0, #Hw_BR9600_13 @ load 13MHz value if bit set moveq r0, #Hw_BR9600 @ if not set, load other divisor orr r0, r0, #Hw_WRDLEN8 @ insert 8-bit character mode str r0, [r12, #Hw_UBRLCR1] mov r0, #StartFlag str r0, [r12, #Hw_UARTDR1] @ receive the date @ store bytes at r9 address, stop loop when r8==r9 @ leaves r8 set to 0x10000800 @ wait for byte to be available uart_ready_loop: ldr r1, [r12, #Hw_SYSFLG] @ spin, if ex fifo is empty tst r1, #Hw_URXFE1 bne uart_ready_loop @ read the data, store it, and accumulate checksum ldr r0, [r12, #Hw_UARTDR1] @read data strb r0, [r8], #1 @ save it in memory cmp r8, r9 blt uart_ready_loop @ all received, send end flag mov r0, #EndFlag strb r0, [r12, #Hw_UARTDR1] @ send reply @ having loaded all the bytes, do the right thing to finish ldrb r0, [r8, #(3-ImageSize)] cmp r0, #BootImageFlagByte moveq pc, r14 @ return to caller for secure image add r10, r12, #WWWWWWWWWW @ r10 = 0x80002400 str r12, [r10, #(ZZZZZZZZZZZ - YYYYYYYYYY)] sub pc, r8, #ImageSize @ branch to 0x10000000 uart_checksum: dcd 0x436b74ab assert(. - start_of_rom) = 640 @ check that it is in the right place end