65 lines
1.1 KiB
ArmAsm
65 lines
1.1 KiB
ArmAsm
/* https://github.com/cirosantilli/x86-bare-metal-examples#rct */
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/* TODO what do those numbers mean? Where is this all documented? */
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.equ RTCaddress, 0x70
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.equ RTCdata, 0x71
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#include "common.h"
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BEGIN
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update_in_progress:
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mov $10, %al
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out %al, $RTCaddress
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in $RTCdata, %al
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testb $0x80, %al
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jne update_in_progress
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/* Second. */
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mov $0, %al
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out %al, $RTCaddress
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in $RTCdata, %al
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/* Only print if second changed. */
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cmp %al, %cl
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je update_in_progress
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mov %al, %cl
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PRINT_HEX <%al>
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PUTC
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/* Minute. */
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mov $0x02, %al
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out %al, $RTCaddress
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in $RTCdata, %al
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PRINT_HEX <%al>
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PUTC
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/* Hour. */
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mov $0x04, %al
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out %al, $RTCaddress
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in $RTCdata, %al
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PRINT_HEX <%al>
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PUTC
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/* Day. */
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mov $0x07, %al
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out %al, $RTCaddress
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in $RTCdata, %al
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PRINT_HEX <%al>
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PUTC
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/* Month. */
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mov $0x08, %al
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out %al, $RTCaddress
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in $RTCdata, %al
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PRINT_HEX <%al>
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PUTC
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/* Year. */
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mov $0x09, %al
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out %al, $RTCaddress
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in $RTCdata, %al
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PRINT_HEX <%al>
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PRINT_NEWLINE
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jmp update_in_progress
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