📄 bbu_uart.s
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; No parameters required
;
; NOTES:
;
; 1. The selected UART port must be initalized first - otherwise this will hang the system!
;
; Control is passed back to the caller only after the transmitter buffer has been emptied of
; all characters on the FIFO buffer.
;
BBU_FF_TXempty FUNCTION
stmfd sp!, {r0, r1, lr} ; Save r0, r1 and link register on the stack
ldr r1, =bbu_FFUART_PHYSICAL_BASE
102 ldr r0, [r1, #bbu_UALSR_offset] ; Get Line Status Register Data
ands r0, r0, #bbu_TEMT ; Is TDRQ (Transmit Data Request) bit set?
beq %B102 ; No - loop until it is
ldmfd sp!, {r0, r1, pc} ; Restore r0, r1 and return to caller
ENDFUNC
;
;*********************************************************************************
;
; ******************
; * *
; * BBU_ST_TXempty * Subroutine
; * *
; ******************
;
; This subroutine does not return to the caller until the Standard UART
; transmitter buffer is empty
;
; PARAMETER PASSING:
;
; No parameters required
;
; NOTES:
;
; 1. The selected UART port must be initalized first - otherwise this will hang the system!
;
; Control is passed back to the caller only after the transmitter buffer has been emptied of
; all characters on the FIFO buffer.
;
BBU_ST_TXempty FUNCTION
stmfd sp!, {r0, r1, lr} ; Save r0, r1 and link register on the stack
ldr r1, =bbu_STUART_PHYSICAL_BASE
102 ldr r0, [r1, #bbu_UALSR_offset] ; Get Line Status Register Data
ands r0, r0, #bbu_TEMT ; Is TDRQ (Transmit Data Request) bit set?
beq %B102 ; No - loop until it is
ldmfd sp!, {r0, r1, pc} ; Restore r0, r1 and return to caller
ENDFUNC
;*********************************************************************************
;
; *******************
; * *
; * BBU_ASCII_value * Converts 32-bit value into ASCII
; * *
; *******************
;
; This subroutine takes the 32 bit value in r0, converts it to four ASCII characters
; and outputs the data to the UART.
;
; PARAMETER PASSING:
;
; r0 contains the 32 bit value to be converted into ASCII text
;
; NOTES:
;
; 1. The selected UART port must be initalized first - otherwise this will hang!
;
BBU_ASCII_value FUNCTION
stmfd sp!, {r1, lr} ; Save r1 and link register on the stack
mov r1, r0 ; Copy value to r2
and r0, r1, #0xFF ; Get the first byte
cmp r0, #0X20 ; Check for low end of valid range
movlt r0, #'.' ; If .LT. above value, replace with period
cmp r0, #0X7E ; Check for high end of valid range
movgt r0, #'.' ; If .GT. abive value, replace with period
bl BBU_putchr ; Output character
and r0, r1, #0xFF00 ; Get the second byte
mov r0, r0, LSR #8 ; and move to lowest 8 bits
cmp r0, #0X20 ; Check for low end of valid range
movlt r0, #'.' ; If .LT. above value, replace with period
cmp r0, #0X7E ; Check for high end of valid range
movgt r0, #'.' ; If .GT. abive value, replace with period
bl BBU_putchr ; Output character
and r0, r1, #0xFF0000 ; Get the third byte
mov r0, r0, LSR #16 ; and move to lowest 8 bits
cmp r0, #0X20 ; Check for low end of valid range
movlt r0, #'.' ; If .LT. above value, replace with period
cmp r0, #0X7E ; Check for high end of valid range
movgt r0, #'.' ; If .GT. abive value, replace with period
bl BBU_putchr ; Output character
and r0, r1, #0xFF000000 ; Get the fourth byte
mov r0, r0, LSR #24 ; and move to lowest 8 bits
cmp r0, #0X20 ; Check for low end of valid range
movlt r0, #'.' ; If .LT. above value, replace with period
cmp r0, #0X7E ; Check for high end of valid range
movgt r0, #'.' ; If .GT. abive value, replace with period
bl BBU_putchr ; Output character
ldmfd sp!, {r1, pc} ; Restore r1 and return to caller
ENDFUNC
;*********************************************************************************
;
; *******************
; * *
; * BBU_UDecToAscii * Subroutine
; * *
; *******************
;
; This subroutine converts an unsigned 32 bit number to decimal ASCII
;
; PARAMETER PASSING:
;
; INPUTS
;
; r0 = contains the number to be converted
; r1 = format of output as follows for the possible 10 digit output:
; bit 6 = 0 to send output to UART, 1 to send output to buffer in r2
; bit 5 = 0 for no comma delimeters, 1 = comma delimeters
; bit 4 = 0 for no leading spaces before 1st digit, 1 = use spaces
; bits 3:0 = number of digits to force in output (LS digit is ALWAYS displayed)
; r2 = address of internal buffer (ignored if bit 6 of r1 = 0)
;
; OUTPUTS:
;
; r2 = updated pointer (if used on input)
;
BBU_UDecToAscii FUNCTION
;
stmfd sp!, {r0, r1, r3-r7, lr} ; Save used registers
;
; Check for x,000,000,000 digit
;
mov r5, r1 ; Copy output format to r5
mov r6, r2 ; Copy buffer address (if present) to r6
and r4, r5, #0xF ; Put number of forced digits in r4
ldr r1, =1000000000 ; Set up divisor
bl BBU_U32Divide ; Divide
orr r0, r2, #0x30 ; Convert result to ASCII digit
cmp r0, #0x30 ; Is it an ASCII zero?
bne %F20 ; Nope - force printing of digit
cmp r4, #10 ; Print leading zero?
blt %F22 ; No - skip the following
20 ands r7, r5, #0x40 ; UART or buffer output?
strneb r0, [r6], #1 ; Save byte in buffer
bleq BBU_putchr ; Send byte to UART
mov r4, #10 ; Force sucesive zeros to be printed
ands r0, r5, #0x20 ; Print a comma?
beq %F25 ; No - process next digit
mov r0, #',' ; <comma>
ands r7, r5, #0x40 ; UART or buffer output?
strneb r0, [r6], #1 ; Save byte in buffer
bleq BBU_putchr ; Send byte to UART
b %F25 ; Process next digit
22 ands r0, r5, #0x10 ; Output leading space?
beq %F25 ; No - process next digit
mov r0, #' ' ; <space>
ands r7, r5, #0x40 ; UART or buffer output?
strneb r0, [r6], #1 ; Save byte in buffer
bleq BBU_putchr ; Send byte to UART
ands r0, r5, #0x20 ; Output <space> to allow for commas?
beq %F25 ; No - process next digit
mov r0, #' ' ; Yes - load a space
ands r7, r5, #0x40 ; UART or buffer output?
strneb r0, [r6], #1 ; Save byte in buffer
bleq BBU_putchr ; Send byte to UART
;
; Check for x00,000,000 digit
;
25 mov r0, r3 ; Copy remainder to dividend
ldr r1, =100000000 ; Set up divisor
bl BBU_U32Divide ; Divide
orr r0, r2, #0x30 ; Convert to ASCII digit
cmp r0, #0x30 ; Is it an ASCII zero?
bne %F30 ; Nope - force printing of digit
cmp r4, #9 ; Print leading zero?
blt %F32 ; No - skip the following
30 ands r7, r5, #0x40 ; UART or buffer output?
strneb r0, [r6], #1 ; Save byte in buffer
bleq BBU_putchr ; Send byte to UART
mov r4, #10 ; Force sucesive zeros to be printed
b %F35 ; Process next digit
32 ands r0, r5, #0x10 ; Output leading space?
beq %F35 ; No - process next digit
mov r0, #' ' ; <space>
ands r7, r5, #0x40 ; UART or buffer output?
strneb r0, [r6], #1 ; Save byte in buffer
bleq BBU_putchr ; Send byte to UART
;
; Check for x0,000,000 digit
;
35 mov r0, r3 ; Copy remainder to dividend
ldr r1, =10000000 ; Set up divisor
bl BBU_U32Divide ; Divide
orr r0, r2, #0x30 ; Convert to ASCII digit
cmp r0, #0x30 ; Is it an ASCII zero?
bne %F40 ; Nope - force printing of digit
cmp r4, #8 ; Print leading zero?
blt %F42 ; No - skip the following
40 ands r7, r5, #0x40 ; UART or buffer output?
strneb r0, [r6], #1 ; Save byte in buffer
bleq BBU_putchr ; Send byte to UART
mov r4, #10 ; Force sucesive zeros to be printed
b %F45 ; Process next digit
42 ands r0, r5, #0x10 ; Output leading space?
beq %F45 ; No - process next digit
mov r0, #' ' ; <space>
ands r7, r5, #0x40 ; UART or buffer output?
strneb r0, [r6], #1 ; Save byte in buffer
bleq BBU_putchr ; Send byte to UART
;
; Check for x,000,000 digit
;
45 mov r0, r3 ; Copy remainder to dividend
ldr r1, =1000000 ; Set up divisor
bl BBU_U32Divide ; Divide
orr r0, r2, #0x30 ; Convert to ASCII digit
cmp r0, #0x30 ; Is it an ASCII zero?
bne %F50 ; Nope - force printing of digit
cmp r4, #7 ; Print leading zero?
blt %F52 ; No - skip the following
50 ands r7, r5, #0x40 ; UART or buffer output?
strneb r0, [r6], #1 ; Save byte in buffer
bleq BBU_putchr ; Send byte to UART
mov r4, #10 ; Force sucesive zeros to be printed
ands r0, r5, #0x20 ; Print a comma?
beq %F55 ; No - process next digit
mov r0, #',' ; <comma>
ands r7, r5, #0x40 ; UART or buffer output?
strneb r0, [r6], #1 ; Save byte in buffer
bleq BBU_putchr ; Send byte to UART
b %F55 ; Process next digit
52 ands r0, r5, #0x10 ; Output leading space?
beq %F55 ; No - process next digit
mov r0, #' ' ; <space>
ands r7, r5, #0x40 ; UART or buffer output?
strneb r0, [r6], #1 ; Save byte in buffer
bleq BBU_putchr ; Send byte to UART
ands r0, r5, #0x20 ; Output <space> to allow for commas?
beq %F55 ; No - process next digit
mov r0, #' ' ; Yes - load a space
ands r7, r5, #0x40 ; UART or buffer output?
strneb r0, [r6], #1 ; Save byte in buffer
bleq BBU_putchr ; Send byte to UART
;
; Check for x00,000 digit
;
55 mov r0, r3 ; Copy remainder to dividend
ldr r1, =100000 ; Set up divisor
bl BBU_U32Divide ; Divide
orr r0, r2, #0x30 ; Convert to ASCII digit
cmp r0, #0x30 ; Is it an ASCII zero?
bne %F60 ; Nope - force printing of digit
cmp r4, #6 ; Print leading zero?
blt %F62 ; No - skip the following
60 ands r7, r5, #0x40 ; UART or buffer output?
strneb r0, [r6], #1 ; Save byte in buffer
bleq BBU_putchr ; Send byte to UART
mov r4, #10 ; Force sucesive zeros to be printed
b %F65 ; Process next digit
62 ands r0, r5, #0x10 ; Output leading space?
beq %F65 ; No - process next digit
mov r0, #' ' ; <space>
ands r7, r5, #0x40 ; UART or buffer output?
strneb r0, [r6], #1 ; Save byte in buffer
bleq BBU_putchr ; Send byte to UART
;
; Check for x0,000 digit
;
65 mov r0, r3 ; Copy remainder to dividend
ldr r1, =10000 ; Set up divisor
bl BBU_U32Divide ; Divide
orr r0, r2, #0x30 ; Convert to ASCII digit
cmp r0, #0x30 ; Is it an ASCII zero?
bne %F70 ; Nope - force printing of digit
cmp r4, #5 ; Print leading zero?
blt %F72 ; No - skip the following
70 ands r7, r5, #0x40 ; UART or⌨️ 快捷键说明
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