| 1 |
2 |
armando |
; FAT16 READER V.050303 - Armando Astarloa - 16 BIT VER.
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| 2 |
5 |
armando |
; APERT - UPV/EHU 2003 - DISTRIBUTED UNDER GPL LICENSE
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| 3 |
2 |
armando |
;
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| 4 |
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; s0 -> TMP0 s1 -> TMP1 s2 -> TMP2 s3 -> TMP3 s4 -> TMP4 / SECTORS_PER_CLUSTER_READED s5 -> TMP5/SECTOR_WORDS_READED (256 TO 0)
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| 5 |
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; s6 -> TMP s7 -> SECTORS_PER_CLUSTER s8 -> CLUSTER_BEGIN_LBA0 (FAT) s9 -> CLUSTER_BEGIN_LBA1 sA -> CLUSTER_BEGIN_LBA2
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| 6 |
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; sB -> CLUSTER_BEGIN_LBA3 sC -> ROOT_DIRECTORY_FIRST_CLUSTER0 (SUPPOSED LESS THAN 256 - USUALLY 2)
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| 7 |
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; sD -> data[7:0] WB MASTER sE -> data[15:8] WB MASTER sF -> acummulator
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| 8 |
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CONSTANT DATA_WB_OUT_7_0_MASTER,00
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| 9 |
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CONSTANT DATA_WB_OUT_15_8_MASTER,01
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| 10 |
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CONSTANT CONTROL_WB_OUT_MASTER,02
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| 11 |
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; D7 = D6 = D5 = D4 = D3 = D2 = A0_MASTER D1 = W_WE_MASTER D0 = STB_O_MASTER
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| 12 |
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; STROBE_O_MASTER = 1 & W_WE=0 & WB_A0 = 0
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| 13 |
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CONSTANT READ_SLAVE,01
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| 14 |
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; STROBE_O_MASTER = 1 & W_WE=1 & WB_A0 = 0
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| 15 |
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CONSTANT WRITE_LBA_15_0,03
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| 16 |
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; STROBE_CF_READER = 1 & W_WE=1 & WB_A0 = 1
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| 17 |
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CONSTANT WRITE_LBA_27_16,07
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| 18 |
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;--
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| 20 |
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;-- SLAVE INTERFACE
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| 21 |
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;--
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| 22 |
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CONSTANT DATA_WB_OUT_7_0_SLAVE,03
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| 23 |
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CONSTANT DATA_WB_OUT_15_8_SLAVE,04
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| 24 |
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CONSTANT CONTROL_WB_OUT_SLAVE,05
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| 25 |
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; D7 = D6 = D5 D4 = D3 =
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| 26 |
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; D2 = TAG1_ERROR
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| 27 |
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; D1 = TAG0_WORD_AVAILABLE
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| 28 |
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; D0 = ACK_O_SLAVE
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| 29 |
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CONSTANT ACK_O_SLAVE,01
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| 30 |
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CONSTANT TAG0_WORD_AVAILABLE,02
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| 31 |
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CONSTANT ERROR,04
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| 32 |
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| 33 |
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;--
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| 34 |
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;-- BUS CONTROL SIGNALS
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| 35 |
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;--
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| 36 |
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CONSTANT CONTROL_OUT_MASTER,06
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| 37 |
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; D7 = D6 = D5 = D4 = D3 = D2 = D1 =
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| 38 |
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; D0 = WB_BUS_MASTER_WRITE_ENABLE
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| 39 |
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CONSTANT WB_BUS_MASTER_WRITE_ENABLE,01
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| 40 |
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CONSTANT CONTROL_OUT_SLAVE,07
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| 41 |
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; D7 = D6 = D5 = D4 = D3 = D2 = D1 =
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| 42 |
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; D0 = WB_BUS_SLAVE_WRITE_ENABLE
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| 43 |
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CONSTANT WB_BUS_SLAVE_WRITE_ENABLE,01
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| 44 |
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;--
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| 45 |
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;-- EXTERNAL REGISTERS FOR MORE DATA ALLOCATION (OTHER OPTION IS THE USE OF
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| 46 |
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;-- ANOTHER BLOCK RAM IF IT IS AVALIABLE
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| 47 |
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;--
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| 48 |
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CONSTANT TMP_OUT_0,08
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| 49 |
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CONSTANT TMP_OUT_1,09
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| 50 |
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CONSTANT TMP_OUT_2,0A
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| 51 |
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CONSTANT TMP_OUT_3,0B
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| 52 |
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CONSTANT TMP_OUT_4,0C
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CONSTANT TMP_OUT_5,0D
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CONSTANT TMP_OUT_6,0E
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CONSTANT TMP_OUT_7,0F
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;--
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;-- INPUT PORTS
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;--
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;--
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;-- WISHBONE INTERFACE PORTS - INPUTS
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;--
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CONSTANT CONTROL_WB_IN_MASTER,00
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; D7 = D6 = D5 = D4 = D3 = D2 =
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; D1 = ERROR_INPUT
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; D0 = ACK_I_MASTER
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;
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CONSTANT ACK_I_MASTER,01
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| 68 |
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CONSTANT ERROR_INPUT,02
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CONSTANT CONTROL_WB_IN_SLAVE,01
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; D7 = D6 = D5 = D4 = D3 = D2 =
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; D1 = -
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| 72 |
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; D0 = STB_I_SLAVE
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| 73 |
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;
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CONSTANT STB_I_SLAVE,01
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;CONSTANT TAG0_FORCE_RESET,02
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;--
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| 77 |
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;-- WISHBONE INTERFACE PORTS - INPUTS
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| 78 |
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;--
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| 79 |
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CONSTANT DATA_WB_IN_7_0_MASTER,02
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| 80 |
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CONSTANT DATA_WB_IN_15_8_MASTER,03
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| 81 |
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;--
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| 82 |
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;-- EXTERNAL REGISTERS FOR MORE DATA ALLOCATION (OTHER OPTION IS THE USE OF
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| 83 |
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;-- ANOTHER BLOCK RAM IF IT IS AVALIABLE
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| 84 |
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;--
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| 85 |
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CONSTANT TMP_IN_0,04
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| 86 |
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CONSTANT TMP_IN_1,05
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| 87 |
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CONSTANT TMP_IN_2,06
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| 88 |
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CONSTANT TMP_IN_3,07
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| 89 |
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CONSTANT TMP_IN_4,08
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| 90 |
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CONSTANT TMP_IN_5,09
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| 91 |
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CONSTANT TMP_IN_6,0A
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| 92 |
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CONSTANT TMP_IN_7,0B
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| 93 |
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;--
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| 94 |
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;-- REGISTERS INITIALIZATION
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| 95 |
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;--
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| 96 |
5 |
armando |
initialization:
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| 97 |
2 |
armando |
;
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| 98 |
5 |
armando |
; WISHBONE INTERFACES INITIALIZATION
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| 99 |
2 |
armando |
;
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| 100 |
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LOAD sF,00
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| 101 |
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OUTPUT sF,DATA_WB_OUT_7_0_MASTER
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| 102 |
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OUTPUT sF,DATA_WB_OUT_15_8_MASTER
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| 103 |
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OUTPUT sF,DATA_WB_OUT_7_0_SLAVE
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| 104 |
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OUTPUT sF,DATA_WB_OUT_15_8_SLAVE
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| 105 |
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OUTPUT sF,CONTROL_WB_OUT_MASTER
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| 106 |
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OUTPUT sF,CONTROL_WB_OUT_SLAVE
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| 107 |
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;
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| 108 |
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; WAIT FOR 410NS*3 (RESET DELAY)
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| 109 |
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| 110 |
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main:
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| 111 |
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| 112 |
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; PROCESS MASTER BOOT RECORD
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| 113 |
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CALL process_master_boot_record
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| 114 |
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; PROCESS ROOT DIRECTORY
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| 115 |
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CALL process_root_directory
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| 116 |
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| 117 |
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start:
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| 118 |
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CALL cluster_2_lba
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| 119 |
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;CALL write_lba_to_slave
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| 120 |
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; sector_per_cluster -> sector_per_cluster_readed
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| 121 |
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LOAD s4,s7
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| 122 |
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; 256 -> (s6) SECTOR_WORDS_READED
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| 123 |
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CALL read_sector
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| 124 |
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idle:
|
| 125 |
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INPUT s6,CONTROL_WB_IN_SLAVE
|
| 126 |
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; CHECK STB INPUT
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| 127 |
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; CONTROL_WB_IN_SLAVE-> TMP (s6)
|
| 128 |
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; IF STB=1 GO TO THE NEXT STATE
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| 129 |
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; IF STB=0 GO TO THE IDLE STATE
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| 130 |
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AND s6,STB_I_SLAVE
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| 131 |
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JUMP Z,idle
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| 132 |
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transfer_word_to_master:
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| 133 |
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CALL read_word_from_slave
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| 134 |
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CALL write_a_word_to_master
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| 135 |
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; (SECTOR WORDS READED)-1
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| 136 |
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SUB s5,01
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| 137 |
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check_sectors_words_readed:
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| 138 |
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; IF sector_words_readed = 0 THEN READ_NEW_SECTOR
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| 139 |
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; IF sector_words_readed > 0 THEN TRANSFER_WORD_TO_MASTER
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| 140 |
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AND s5,s5
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| 141 |
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CALL Z,check_sector_per_cluster_readed
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| 142 |
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JUMP idle
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| 143 |
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track_new_cluster:
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| 144 |
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; save the number of dummy reads that must be done when the fat sector will be readed
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| 145 |
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; an are stored into s5 register
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| 146 |
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; in s0 bits 6-0 of the cluster number (offset in the sector -> 256 words-fat16 entries)
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| 147 |
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; as is each read operation a word is readed no multiplication is needed
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| 148 |
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; RESTORE CLUSTER NUMBER
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| 149 |
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INPUT s0,TMP_IN_4
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| 150 |
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INPUT s1,TMP_IN_5
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| 151 |
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INPUT s2,TMP_IN_6
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| 152 |
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INPUT s3,TMP_IN_7
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| 153 |
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;
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| 154 |
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; compose LBA address of the sector of the fat that must be readed
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| 155 |
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;
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| 156 |
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; SHIFT RIGHT 15-8 TO 7-0
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| 157 |
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;
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| 158 |
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LOAD sF,07
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| 159 |
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do_shift:
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| 160 |
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SR0 s3
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| 161 |
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; uses the carry for the MSB and stores LSB into the carry
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| 162 |
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SRA s2
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| 163 |
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SRA s1
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| 164 |
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SRA s0
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| 165 |
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SUB sF,01
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| 166 |
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JUMP NZ,do_shift
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| 167 |
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CALL add_load_fat_begin_lba
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| 168 |
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; adds fat_begin_lba to the sector relative to the fat obteined from the cluster
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| 169 |
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; now there is the lba of the FAT sector that must be readed in s0,s1,s2,s3
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| 170 |
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CALL write_lba_to_slave
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| 171 |
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; -- DUMMY READ OF THE WORDS OF THE SECTOR TILL THE ONE OF THE CLUSTER INTEGER
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| 172 |
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INPUT sF,TMP_IN_4
|
| 173 |
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AND sF,7F
|
| 174 |
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CALL do_dummy_reads_from_slave
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| 175 |
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;
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| 176 |
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; (sD) data[7:0] WB MASTER -> (s0) TEMPORAL REGISTER
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| 177 |
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; (sE) data[7:0] WB MASTER -> (s1) TEMPORAL REGISTER
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| 178 |
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; READ 2 BYTES
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| 179 |
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CALL read_word_from_slave
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| 180 |
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LOAD s0,sD
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| 181 |
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LOAD s1,sE
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| 182 |
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; (sD) data[7:0] WB MASTER -> (s2) TEMPORAL REGISTER
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| 183 |
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; (sE) data[7:0] WB MASTER -> (s3) TEMPORAL REGISTER
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| 184 |
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; READ 2 BYTES
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| 185 |
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;
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| 186 |
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; CHECK IF ITS THE LAST ONE
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| 187 |
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; CB3-CL2-CB1-CB0 IN FAT LITTLE ENDIAN ORDER CB0-CB1 CB2-CB3
|
| 188 |
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LOAD sF,sE
|
| 189 |
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SUB sF,FF
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| 190 |
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JUMP NZ,continue_file_processing
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| 191 |
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LOAD sF,sD
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| 192 |
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SUB sF,FF
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| 193 |
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JUMP NZ,continue_file_processing
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| 194 |
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file_end:
|
| 195 |
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; infinite loop (file readed and tranferred)
|
| 196 |
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JUMP file_end
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| 197 |
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continue_file_processing:
|
| 198 |
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; in s0,s1 is the cluster name
|
| 199 |
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; --
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| 200 |
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; (SECTOR WORDS READED)= 256
|
| 201 |
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; sector_per_cluster -> sector_per_cluster_readed
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| 202 |
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LOAD s2,00
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| 203 |
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LOAD s3,00
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| 204 |
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LOAD s4,s7
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| 205 |
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CALL cluster_2_lba
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| 206 |
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CALL read_sector
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| 207 |
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RETURN
|
| 208 |
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| 209 |
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add_load_fat_begin_lba:
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| 210 |
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INPUT sF,TMP_IN_0
|
| 211 |
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ADD s0,sF
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| 212 |
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INPUT sF,TMP_IN_1
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| 213 |
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ADDCY s1,sF
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| 214 |
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INPUT sF,TMP_IN_2
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| 215 |
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ADDCY s2,sF
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| 216 |
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INPUT sF,TMP_IN_3
|
| 217 |
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ADDCY s3,sF
|
| 218 |
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RETURN
|
| 219 |
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|
| 220 |
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check_sector_per_cluster_readed:
|
| 221 |
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; IF sector_per_cluster_readed = 0 THEN TRACK_NEW_CLUSTER
|
| 222 |
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; IF sector_per_cluster_readed > 0 THEN CHECK SECTOR WORDS READED
|
| 223 |
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; (sector_per_cluster_readed)-1
|
| 224 |
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; (SECTOR WORDS READED)= 256
|
| 225 |
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SUB s4,01
|
| 226 |
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AND s4,s4
|
| 227 |
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JUMP Z,track_new_cluster
|
| 228 |
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read_new_sector:
|
| 229 |
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; (SECTOR WORDS READED)= 256
|
| 230 |
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; increment LBA
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| 231 |
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; sector_per_cluster -> sector_per_cluster_readed-1
|
| 232 |
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ADD s0,01
|
| 233 |
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ADDCY s1,00
|
| 234 |
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ADDCY s2,00
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| 235 |
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ADDCY s3,00
|
| 236 |
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read_sector:
|
| 237 |
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LOAD s5,00
|
| 238 |
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CALL write_lba_to_slave
|
| 239 |
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RETURN
|
| 240 |
|
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;
|
| 241 |
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; --
|
| 242 |
|
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; -- PROCESS MASTER BOOT RECORD (READ LBA BEGIN OF THE FIRST PARTITION)
|
| 243 |
|
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; --
|
| 244 |
|
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process_master_boot_record:
|
| 245 |
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;
|
| 246 |
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; LOAD LBA FOR MBR READ
|
| 247 |
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;
|
| 248 |
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LOAD s0,00
|
| 249 |
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LOAD s1,00
|
| 250 |
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LOAD s2,00
|
| 251 |
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LOAD s3,00
|
| 252 |
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CALL write_lba_to_slave
|
| 253 |
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; information of the lba begin for the first partition
|
| 254 |
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; has an offset of 454 bytes -> 227(0xE3) words
|
| 255 |
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LOAD sF,E3
|
| 256 |
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CALL do_dummy_reads_from_slave
|
| 257 |
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;
|
| 258 |
|
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; --
|
| 259 |
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; -- MBR READ - Partition_LBA_Begin EXTRACTION
|
| 260 |
|
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; --
|
| 261 |
|
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;
|
| 262 |
|
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; (sD) data[7:0] WB MASTER -> (s0) lba
|
| 263 |
|
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; (sE) data[15:8] WB MASTER -> (s1) lba
|
| 264 |
|
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; (sD) data[7:0] WB MASTER -> (s2) lba
|
| 265 |
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; (sE) data[15:8] WB MASTER -> (s3) lba
|
| 266 |
|
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call store_all_temporal_registers
|
| 267 |
|
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LOAD s8,s0
|
| 268 |
|
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LOAD s9,s1
|
| 269 |
|
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LOAD sA,s2
|
| 270 |
|
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LOAD sB,s3
|
| 271 |
|
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;
|
| 272 |
|
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; NOW IS THE LBA_BEGIN ON THE TMP REGISTERS
|
| 273 |
|
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; --------------------
|
| 274 |
|
|
; READ FIRST SECTOR (FAT32 VOLUMEN ID) OF THE PARTITION
|
| 275 |
|
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; ---------------------
|
| 276 |
|
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CALL write_lba_to_slave
|
| 277 |
|
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;
|
| 278 |
|
|
; READ -> SECTORS_PER_CLUSTER (OFFSET 0x0D)
|
| 279 |
|
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;
|
| 280 |
|
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; offset 0x0D (13) => READ 13 bytes -> 6(0x06) words and drop LSB in the next
|
| 281 |
|
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LOAD sF,06
|
| 282 |
|
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CALL do_dummy_reads_from_slave
|
| 283 |
|
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;
|
| 284 |
|
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; (sE) data[7:0] WB MASTER -> (s7) SECTORS PER CLUSTER
|
| 285 |
|
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CALL read_word_from_slave
|
| 286 |
|
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LOAD s7,sE
|
| 287 |
|
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;
|
| 288 |
|
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; READ -> Number_of_Reserved_Sectors (2 bytes) (OFFSET 0x0E)
|
| 289 |
|
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;
|
| 290 |
|
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; offset 0x0E (14) => READ 2 bytes -> 1(0x01) words
|
| 291 |
|
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; (sD) data[15:8] WB MASTER -> (s6) TEMPORAL REGISTER
|
| 292 |
|
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CALL read_word_from_slave
|
| 293 |
|
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LOAD s6,sD
|
| 294 |
|
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; (sE) data[7:0] WB MASTER -> (s4) TEMPORAL REGISTER
|
| 295 |
|
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;
|
| 296 |
|
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LOAD s4,sE
|
| 297 |
|
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;
|
| 298 |
|
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;fat_begin_lba = Partition_LBA_Begin + Number_of_Reserved_Sectors
|
| 299 |
|
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;
|
| 300 |
|
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ADD s8,s6
|
| 301 |
|
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ADDCY s9,s4
|
| 302 |
|
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ADDCY sA,00
|
| 303 |
|
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ADDCY sB,00
|
| 304 |
|
|
; store fat_begin_lba in external registers
|
| 305 |
|
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OUTPUT s8,TMP_OUT_0
|
| 306 |
|
|
OUTPUT s9,TMP_OUT_1
|
| 307 |
|
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OUTPUT sA,TMP_OUT_2
|
| 308 |
|
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OUTPUT sB,TMP_OUT_3
|
| 309 |
|
|
;
|
| 310 |
|
|
;cluster_begin_lba = Partition_LBA_Begin + Number_of_Reserved_Sectors +
|
| 311 |
|
|
; (Number_of_FATs * Sectors_Per_FAT)+ RootDirSectors;
|
| 312 |
|
|
;cluster_begin_lba = fat_begin_lba + (Number_of_FATs * Sectors_Per_FAT)+ RootDirSectors;
|
| 313 |
|
|
; READ -> Number_of_Fats (OFFSET 0x10) (always 2)
|
| 314 |
|
|
;
|
| 315 |
|
|
; offset 0x10 (16) => READ 2 bytes -> 1(0x01) words
|
| 316 |
|
|
;
|
| 317 |
|
|
; (sD) data[7:0] WB MASTER -> (s6) TEMPORAL REGISTER
|
| 318 |
|
|
CALL read_word_from_slave
|
| 319 |
|
|
LOAD s6,sD
|
| 320 |
|
|
;
|
| 321 |
|
|
; FOR FAT16 => NUMBER OF SECTORS OCCUPIED BY THE ROOT DIRECTORY (BYTES_PER_SEC=512)
|
| 322 |
|
|
;
|
| 323 |
|
|
; READ -> RootEntCnt (OFFSET 0x11) (FAT16 PROCESSING)
|
| 324 |
|
|
; RootDirSectors=((BPB_RootEntCnt*32)+(BPB_BytesPerSec-1))/BPB_BytesPerSec
|
| 325 |
|
|
; offset 0x11 (17) => READ 1 bytes
|
| 326 |
|
|
;
|
| 327 |
|
|
; (sE) data[7:0] WB MASTER -> (s0) TEMPORAL REGISTER
|
| 328 |
|
|
LOAD s0,sE
|
| 329 |
|
|
; (sD) data[15:0] WB MASTER -> (sD) TEMPORAL REGISTER - offset 0x12 (18) => READ 1 bytes
|
| 330 |
|
|
CALL read_word_from_slave
|
| 331 |
|
|
LOAD s1,sD
|
| 332 |
|
|
; MULTIPLY BY 32 (100000) 5 SHIFTS TO THE LEFT
|
| 333 |
|
|
LOAD sF,05
|
| 334 |
|
|
; LSB '0'
|
| 335 |
|
|
mult_32:
|
| 336 |
|
|
SL0 s0
|
| 337 |
|
|
; CARRY -> LSB , MSB -> CARRY
|
| 338 |
|
|
SLA s1
|
| 339 |
|
|
SUB sF,01
|
| 340 |
|
|
JUMP NZ,mult_32
|
| 341 |
|
|
;BPB_RootEntCnt*32+(BPB_BytesPerSec-1) 511 (0x1FF)
|
| 342 |
|
|
;ADD s0,FF (if rounds up => not necessary??)
|
| 343 |
|
|
;ADDCY s1,01
|
| 344 |
|
|
;/BPB_BytesPerSec (512) (1000000000)9 SHIFTS TO THE RIGHT
|
| 345 |
|
|
LOAD sF,09
|
| 346 |
|
|
div_512:
|
| 347 |
|
|
; uses the carry for the MSB and stores LSB into the carry
|
| 348 |
|
|
SR0 s1
|
| 349 |
|
|
SRA s0
|
| 350 |
|
|
SUB sF,01
|
| 351 |
|
|
JUMP NZ,div_512
|
| 352 |
|
|
; ROUNDs UP
|
| 353 |
|
|
;ADD s0,01
|
| 354 |
|
|
;ADDCY s1,00
|
| 355 |
|
|
;fat_begin_lba + RootDirSectors
|
| 356 |
|
|
ADD s8,s0
|
| 357 |
|
|
ADDCY s9,s1
|
| 358 |
|
|
ADDCY sA,s2
|
| 359 |
|
|
ADDCY sB,s3
|
| 360 |
|
|
; READ -> Sectors_per_fat (OFFSET 0x24)
|
| 361 |
|
|
;
|
| 362 |
|
|
; offset 0x16 (22) => READ 2 bytes -> 01(0x01) words
|
| 363 |
|
|
;
|
| 364 |
|
|
LOAD sF,01
|
| 365 |
|
|
CALL do_dummy_reads_from_slave
|
| 366 |
|
|
CALL store_all_temporal_registers
|
| 367 |
|
|
; (Number_of_FATs * Sectors_Per_FAT)
|
| 368 |
|
|
; Number_of_FATs = 2 (10) . Do a shift to the left of the Sectors_Per_Fat
|
| 369 |
|
|
; *** FAT16 = Sectors_per_fat(BPB_FATSz16)
|
| 370 |
|
|
; LSB '0'
|
| 371 |
|
|
SL0 s0
|
| 372 |
|
|
; CARRY -> LSB , MSB -> CARRY
|
| 373 |
|
|
SLA s1
|
| 374 |
|
|
;SLA s2 for fat16 only 2 bytes
|
| 375 |
|
|
;SLA s3
|
| 376 |
|
|
; fat_begin_lba + RootDirSectors + (Number_of_FATs * Sectors_Per_FAT)
|
| 377 |
|
|
ADD s8,s0
|
| 378 |
|
|
ADDCY s9,s1
|
| 379 |
|
|
ADDCY sA,00
|
| 380 |
|
|
ADDCY sB,00
|
| 381 |
|
|
; cluster_begin_lba is stored in s8, s9, sA, SB
|
| 382 |
|
|
;
|
| 383 |
|
|
; FOR FAT16 ROOT DIRECTORY POSITION IS FIXED
|
| 384 |
|
|
; root_first_lba = fat_begin_lba(in external regs) + (Number_of_FATs * Sectors_Per_FAT) (s0,s1,s2,s3)
|
| 385 |
|
|
;
|
| 386 |
|
|
LOAD s2,00
|
| 387 |
|
|
LOAD s3,00
|
| 388 |
|
|
CALL add_load_fat_begin_lba
|
| 389 |
|
|
; s0,s1,s2,s3 have Root directory begin lba
|
| 390 |
|
|
RETURN
|
| 391 |
|
|
|
| 392 |
|
|
store_all_temporal_registers:
|
| 393 |
|
|
; READ 2 BYTES
|
| 394 |
|
|
CALL read_word_from_slave
|
| 395 |
|
|
; (sD) data[7:0] WB MASTER -> (s0) TEMPORAL REGISTER
|
| 396 |
|
|
; (sE) data[7:0] WB MASTER -> (s1) TEMPORAL REGISTER
|
| 397 |
|
|
LOAD s0,sD
|
| 398 |
|
|
LOAD s1,sE
|
| 399 |
|
|
; (sD) data[7:0] WB MASTER -> (s2) TEMPORAL REGISTER
|
| 400 |
|
|
; (sE) data[7:0] WB MASTER -> (s3) TEMPORAL REGISTER
|
| 401 |
|
|
; READ 2 BYTES
|
| 402 |
|
|
CALL read_word_from_slave
|
| 403 |
|
|
LOAD s2,sD
|
| 404 |
|
|
LOAD s3,sE
|
| 405 |
|
|
RETURN
|
| 406 |
|
|
process_root_directory:
|
| 407 |
|
|
; INPUT :
|
| 408 |
|
|
; s0,s1,s2,s3 root directory lba (FAT16- FIXED)
|
| 409 |
|
|
; CALL cluster_2_lba
|
| 410 |
|
|
; now s0,s1,s2,s3 contains the lba for the root directory
|
| 411 |
|
|
; the first 32 byte record on the sector must be the root directory information
|
| 412 |
|
|
; check if EOF (first byte of the 32 bytes is 0)
|
| 413 |
|
|
CALL write_lba_to_slave
|
| 414 |
|
|
check_for_a_file:
|
| 415 |
|
|
CALL read_word_from_slave
|
| 416 |
|
|
; (sD) data[7:0] WB MASTER -> (s6) TEMPORAL REGISTER
|
| 417 |
|
|
LOAD s6,sD
|
| 418 |
|
|
LOAD sF,s6
|
| 419 |
|
|
AND sF,sF
|
| 420 |
|
|
; if sF=0 the is not directory => error
|
| 421 |
|
|
JUMP Z,put_error_code
|
| 422 |
|
|
;
|
| 423 |
|
|
; check that is not a deleted entry
|
| 424 |
|
|
;
|
| 425 |
|
|
; (sD) data[7:0] WB MASTER -> (s6) TEMPORAL REGISTER
|
| 426 |
|
|
LOAD sF,E5
|
| 427 |
|
|
AND sF,s6
|
| 428 |
|
|
; if s6=E5 is a deteled entry => check for new one (offset => sF)
|
| 429 |
|
|
JUMP Z,check_next_directory_entry
|
| 430 |
|
|
check_attribute:
|
| 431 |
|
|
; ATTRIBUTE -> OFFSET Bh
|
| 432 |
|
|
; check that is not a directory or LONG NAME
|
| 433 |
|
|
; 00arshdv - DV for long name - D for directory
|
| 434 |
|
|
; (sD) data[7:0] WB MASTER -> (s6) TEMPORAL REGISTER
|
| 435 |
|
|
LOAD sF,04
|
| 436 |
|
|
CALL do_dummy_reads_from_slave
|
| 437 |
|
|
CALL read_word_from_slave
|
| 438 |
|
|
LOAD s6,sE
|
| 439 |
|
|
LOAD sF,03
|
| 440 |
|
|
AND sF,s6
|
| 441 |
|
|
JUMP NZ,check_next_directory_entry_attribute
|
| 442 |
|
|
; if s6=0 that is not a file => error
|
| 443 |
|
|
;JUMP Z,check_next_directory_entry
|
| 444 |
|
|
; check that is not a directory
|
| 445 |
|
|
; check that is a file (short filename entry)
|
| 446 |
|
|
; in other case error
|
| 447 |
|
|
;
|
| 448 |
|
|
;
|
| 449 |
|
|
; READ CLUSTER INFORMATION FOR THE FILE
|
| 450 |
|
|
;
|
| 451 |
|
|
CALL read_dir_cluster_hi_cluster_low
|
| 452 |
|
|
RETURN
|
| 453 |
|
|
check_next_directory_entry:
|
| 454 |
|
|
; go fwd 11 words
|
| 455 |
|
|
LOAD sF,05
|
| 456 |
|
|
CALL do_dummy_reads_from_slave
|
| 457 |
|
|
check_next_directory_entry_attribute:
|
| 458 |
|
|
; go fwd 5 words
|
| 459 |
|
|
LOAD sF,0A
|
| 460 |
|
|
CALL do_dummy_reads_from_slave
|
| 461 |
|
|
JUMP check_for_a_file
|
| 462 |
|
|
read_dir_cluster_hi_cluster_low:
|
| 463 |
|
|
; INPUT :
|
| 464 |
|
|
; before arrive here first two bytes of the directory
|
| 465 |
|
|
; structure must be readed
|
| 466 |
|
|
; OUTPUT :
|
| 467 |
|
|
; s0,s1 : CLUS_LOW
|
| 468 |
|
|
; s2,s3 : CLUS_HI
|
| 469 |
|
|
;
|
| 470 |
|
|
; READ -> cluster_HI (OFFSET 0x14)
|
| 471 |
|
|
;
|
| 472 |
|
|
; offset 0x14 (20) => READ 18 bytes -> 9(0x09) words
|
| 473 |
|
|
;
|
| 474 |
|
|
LOAD sF,04
|
| 475 |
|
|
CALL do_dummy_reads_from_slave
|
| 476 |
|
|
; (sD) data[7:0] WB MASTER -> s2
|
| 477 |
|
|
; (sE) data[7:0] WB MASTER -> s3
|
| 478 |
|
|
; READ 2 BYTES
|
| 479 |
|
|
CALL read_word_from_slave
|
| 480 |
|
|
LOAD s2,sD
|
| 481 |
|
|
LOAD s3,sE
|
| 482 |
|
|
OUTPUT sE,TMP_OUT_7
|
| 483 |
|
|
;
|
| 484 |
|
|
; READ -> cluster_low(OFFSET 0x1A)
|
| 485 |
|
|
;
|
| 486 |
|
|
; offset 0x1A (26) => READ 4 bytes -> 2(0x02) words
|
| 487 |
|
|
;
|
| 488 |
|
|
LOAD sF,02
|
| 489 |
|
|
CALL do_dummy_reads_from_slave
|
| 490 |
|
|
; (sD) data[7:0] WB MASTER -> s0
|
| 491 |
|
|
; (sE) data[7:0] WB MASTER -> s1
|
| 492 |
|
|
; READ 2 BYTES
|
| 493 |
|
|
CALL read_word_from_slave
|
| 494 |
|
|
LOAD s0,sD
|
| 495 |
|
|
LOAD s1,sE
|
| 496 |
|
|
; s0,s1 clus_low s3,s4 - clus_high
|
| 497 |
|
|
RETURN
|
| 498 |
|
|
|
| 499 |
|
|
; -- MBR READ OPERATION - LBA BEGIN DETERMINATION
|
| 500 |
|
|
; '00' -> LBA_7_0,LBA_15_8,LBA_23_16,LD_LBA_27_24
|
| 501 |
|
|
|
| 502 |
|
|
cluster_2_lba:
|
| 503 |
|
|
; --
|
| 504 |
|
|
; -- LBA ADDRESS DETERMINATION
|
| 505 |
|
|
; --
|
| 506 |
|
|
; lba_addr = cluster_begin_lba + (cluster_number - 2) * sectors_per_cluster;
|
| 507 |
|
|
;
|
| 508 |
|
|
; INPUT :
|
| 509 |
|
|
; s0 : CLUSTER_NUMBER0, s1 : CLUSTER_NUMBER1, s2: CLUSTER_NUMBER2, s3 : CLUSTER_NUMBER3
|
| 510 |
|
|
; OUTPUT :
|
| 511 |
|
|
; s0 : LBA_ADDR_7_0 TMP1, s1 : LBA_ADDR_15_8, s2 : LBA_ADDR_24_16, s3 : LBA_ADDR_27_24
|
| 512 |
|
|
;
|
| 513 |
|
|
; cluster_number - 2
|
| 514 |
|
|
;
|
| 515 |
|
|
OUTPUT s0,TMP_OUT_4
|
| 516 |
|
|
OUTPUT s1,TMP_OUT_5
|
| 517 |
|
|
OUTPUT s2,TMP_OUT_6
|
| 518 |
|
|
OUTPUT s3,TMP_OUT_7
|
| 519 |
|
|
SUB s0,02
|
| 520 |
|
|
SUBCY s1,00
|
| 521 |
|
|
SUBCY s2,00
|
| 522 |
|
|
SUBCY s3,00
|
| 523 |
|
|
;
|
| 524 |
|
|
; (cluster_number - 2) * sectors_per_cluster(s7);
|
| 525 |
|
|
;
|
| 526 |
|
|
; to perform the multiplication as sector_per_cluster is 2 multiple must be known
|
| 527 |
|
|
; who many times must be shifted
|
| 528 |
|
|
; (use sD as temporal register)
|
| 529 |
|
|
LOAD sF,08
|
| 530 |
|
|
LOAD sD,s7
|
| 531 |
|
|
|
| 532 |
|
|
multiply:
|
| 533 |
|
|
SR0 sD
|
| 534 |
|
|
; loop until detection of the 1 (2 multiple) - Add timeout!!!
|
| 535 |
|
|
JUMP C,add_cluster_begin_lba
|
| 536 |
|
|
; LSB '0'
|
| 537 |
|
|
SL0 s0
|
| 538 |
|
|
; CARRY -> LSB , MSB -> CARRY
|
| 539 |
|
|
SLA s1
|
| 540 |
|
|
SLA s2
|
| 541 |
|
|
SLA s3
|
| 542 |
|
|
JUMP multiply
|
| 543 |
|
|
|
| 544 |
|
|
add_cluster_begin_lba:
|
| 545 |
|
|
; lba_addr (TMP0,TMP1,TMP2,TMP3)= cluster_begin_lba + (cluster_number - 2) * sectors_per_cluster;
|
| 546 |
|
|
ADD s0,s8
|
| 547 |
|
|
ADDCY s1,s9
|
| 548 |
|
|
ADDCY s2,sA
|
| 549 |
|
|
ADDCY s3,sB
|
| 550 |
|
|
RETURN
|
| 551 |
|
|
|
| 552 |
|
|
; --
|
| 553 |
|
|
; -- WRITE A WORD INTO THE WB SLAVE INTERFACE (TO THE MASTER)
|
| 554 |
|
|
; --
|
| 555 |
|
|
; INPUTS :
|
| 556 |
|
|
; TMP0 : LSB TO DATA_WB_OUT_7_0_SLAVE
|
| 557 |
|
|
; TMP1 : MSB TO DATA_WB_OUT_15_8_SLAVE
|
| 558 |
|
|
;
|
| 559 |
|
|
write_a_word_to_master:
|
| 560 |
|
|
; TMP0 => DATA_WB_OUT_7_0_SLAVE
|
| 561 |
|
|
OUTPUT sD,DATA_WB_OUT_7_0_SLAVE
|
| 562 |
|
|
; 00 => DATA_WB_OUT_15_8_SLAVE
|
| 563 |
|
|
;LOAD sF,00 -- 8 BIT VERSION
|
| 564 |
|
|
;OUTPUT sF,DATA_WB_OUT_15_8_SLAVE -- 8 BIT VERSION
|
| 565 |
|
|
OUTPUT sE,DATA_WB_OUT_15_8_SLAVE
|
| 566 |
|
|
CALL write_a_byte_to_master
|
| 567 |
|
|
;
|
| 568 |
|
|
; CHECK STB INPUT | CONTROL_WB_IN_SLAVE-> TMP (s6)
|
| 569 |
|
|
;
|
| 570 |
|
|
wait_strobe:
|
| 571 |
|
|
INPUT s6,CONTROL_WB_IN_SLAVE
|
| 572 |
|
|
;
|
| 573 |
|
|
;
|
| 574 |
|
|
AND s6,STB_I_SLAVE
|
| 575 |
|
|
JUMP Z,wait_strobe
|
| 576 |
|
|
; TMP1 => DATA_WB_OUT_7_0_SLAVE
|
| 577 |
|
|
; OUTPUT sE,DATA_WB_OUT_7_0_SLAVE
|
| 578 |
|
|
; 00 =>DATA_WB_OUT_15_8_SLAVE
|
| 579 |
|
|
;LOAD sF,00 -- 8 BIT VERSION
|
| 580 |
|
|
;OUTPUT sF,DATA_WB_OUT_15_8_SLAVE -- 8 BIT VERSION
|
| 581 |
|
|
;CALL write_a_byte_to_master -- 8 BIT VERSION
|
| 582 |
|
|
RETURN
|
| 583 |
|
|
|
| 584 |
|
|
write_a_byte_to_master:
|
| 585 |
|
|
;
|
| 586 |
|
|
; WB SLAVE WRITE ENABLE ACTIVE
|
| 587 |
|
|
;
|
| 588 |
|
|
LOAD sF,WB_BUS_SLAVE_WRITE_ENABLE
|
| 589 |
|
|
OUTPUT sF,CONTROL_OUT_SLAVE
|
| 590 |
|
|
;
|
| 591 |
|
|
; ACK TO THE MASTER UNTIL STB FINISH
|
| 592 |
|
|
;
|
| 593 |
|
|
ack_to_the_master:
|
| 594 |
|
|
LOAD sF,ACK_O_SLAVE
|
| 595 |
|
|
OUTPUT sF,CONTROL_WB_OUT_SLAVE
|
| 596 |
|
|
;
|
| 597 |
|
|
;
|
| 598 |
|
|
LOAD sF,00
|
| 599 |
|
|
OUTPUT sF,CONTROL_OUT_SLAVE
|
| 600 |
|
|
OUTPUT sF,CONTROL_WB_OUT_SLAVE
|
| 601 |
|
|
RETURN
|
| 602 |
|
|
; --
|
| 603 |
|
|
; -- WRITE A LBA INTO THE WB MASTER INTERFACE (TO THE SLAVE)
|
| 604 |
|
|
; --
|
| 605 |
|
|
; INPUTS :
|
| 606 |
|
|
; TMP0 : LBA_ADDR_7_0, TMP1 : LBA_ADDR_15_8, TMP2 : LBA_ADDR_24_16, TMP3 : LBA_ADDR_27_24
|
| 607 |
|
|
;
|
| 608 |
|
|
;
|
| 609 |
|
|
write_lba_to_slave:
|
| 610 |
|
|
;
|
| 611 |
|
|
; WB MASTER WRITE ENABLE ACTIVE
|
| 612 |
|
|
;
|
| 613 |
|
|
LOAD sF,WB_BUS_MASTER_WRITE_ENABLE
|
| 614 |
|
|
OUTPUT sF,CONTROL_OUT_MASTER
|
| 615 |
|
|
|
| 616 |
|
|
;write_lba_15_0_to_slave:
|
| 617 |
|
|
;
|
| 618 |
|
|
; TMP0 : LBA_ADDR_7_0 (s0) => DATA_WB_OUT_7_0_MASTER
|
| 619 |
|
|
; TMP1 : LBA_ADDR_15_8 (s1) => DATA_WB_OUT_15_8_MASTER
|
| 620 |
|
|
;
|
| 621 |
|
|
OUTPUT s0,DATA_WB_OUT_7_0_MASTER
|
| 622 |
|
|
OUTPUT s1,DATA_WB_OUT_15_8_MASTER
|
| 623 |
|
|
;
|
| 624 |
|
|
; --
|
| 625 |
|
|
; -- WRITE LBA 15-0 TO THE SLAVE
|
| 626 |
|
|
; --
|
| 627 |
|
|
;
|
| 628 |
|
|
; WB_CONTROL_OUT_MASTER
|
| 629 |
|
|
; W_WE_MASTER = 1
|
| 630 |
|
|
; STB_O_MASTER = 1
|
| 631 |
|
|
; A0 = 0
|
| 632 |
|
|
;
|
| 633 |
|
|
LOAD sF,WRITE_LBA_15_0
|
| 634 |
|
|
OUTPUT sF,CONTROL_WB_OUT_MASTER
|
| 635 |
|
|
;
|
| 636 |
|
|
; WAIT FOR THE ACK
|
| 637 |
|
|
;
|
| 638 |
|
|
CALL wait_for_the_ack
|
| 639 |
|
|
|
| 640 |
|
|
;write_lba_27_16_to_slave:
|
| 641 |
|
|
;
|
| 642 |
|
|
; TMP2 : LBA_ADDR_23_16 (s2) => DATA_WB_OUT_7_0_MASTER
|
| 643 |
|
|
; TMP3 : LBA_ADDR_27_24 (s3) => DATA_WB_OUT_15_8_MASTER
|
| 644 |
|
|
;
|
| 645 |
|
|
OUTPUT s2,DATA_WB_OUT_7_0_MASTER
|
| 646 |
|
|
OUTPUT s3,DATA_WB_OUT_15_8_MASTER
|
| 647 |
|
|
|
| 648 |
|
|
; --
|
| 649 |
|
|
; -- WRITE LBA 27-16 TO THE SLAVE
|
| 650 |
|
|
; --
|
| 651 |
|
|
; WB_CONTROL_OUT_MASTER
|
| 652 |
|
|
; W_WE_MASTER = 1
|
| 653 |
|
|
; STB_O_MASTER = 1
|
| 654 |
|
|
; A0 = 0
|
| 655 |
|
|
;
|
| 656 |
|
|
LOAD sF,WRITE_LBA_27_16
|
| 657 |
|
|
OUTPUT sF,CONTROL_WB_OUT_MASTER
|
| 658 |
|
|
;
|
| 659 |
|
|
; WAIT FOR THE ACK
|
| 660 |
|
|
;
|
| 661 |
|
|
CALL wait_for_the_ack
|
| 662 |
|
|
; --
|
| 663 |
|
|
; -- FINISH WRITE OPERATION ON THE MASTER WB INTERFACE
|
| 664 |
|
|
; --
|
| 665 |
|
|
;
|
| 666 |
|
|
; WB_CONTROL_OUT_MASTER
|
| 667 |
|
|
; W_WE_MASTER = 0
|
| 668 |
|
|
; STB_O_MASTER = 0
|
| 669 |
|
|
; A0 = 0
|
| 670 |
|
|
;
|
| 671 |
|
|
LOAD sF,00
|
| 672 |
|
|
OUTPUT sF,CONTROL_WB_OUT_MASTER
|
| 673 |
|
|
OUTPUT sF,CONTROL_OUT_MASTER
|
| 674 |
|
|
RETURN
|
| 675 |
|
|
|
| 676 |
|
|
; --
|
| 677 |
|
|
; -- PERFORM DUMMY READS FROM THE WB SLAVE
|
| 678 |
|
|
; --
|
| 679 |
|
|
; -- IN sF ARE THE NUMBER OF WORDS THAT MUST BE READED
|
| 680 |
|
|
; --
|
| 681 |
|
|
do_dummy_reads_from_slave:
|
| 682 |
|
|
LOAD s6,sF
|
| 683 |
|
|
dummy_reads_from_slave:
|
| 684 |
|
|
CALL read_word_from_slave
|
| 685 |
|
|
SUB s6,01
|
| 686 |
|
|
JUMP NZ,dummy_reads_from_slave
|
| 687 |
|
|
RETURN
|
| 688 |
|
|
|
| 689 |
|
|
; --
|
| 690 |
|
|
; -- PERFORM A WORD READING FROM THE WB SLAVE
|
| 691 |
|
|
; --
|
| 692 |
|
|
read_word_from_slave:
|
| 693 |
|
|
; WB_CONTROL_OUT_MASTER
|
| 694 |
|
|
; W_WE_MASTER = 0
|
| 695 |
|
|
; STB_O_MASTER = 1
|
| 696 |
|
|
; A0 = 0
|
| 697 |
|
|
; wait state
|
| 698 |
|
|
LOAD sF,READ_SLAVE
|
| 699 |
|
|
OUTPUT sF,CONTROL_WB_OUT_MASTER
|
| 700 |
|
|
;
|
| 701 |
|
|
; WAIT FOR THE ACK
|
| 702 |
|
|
;
|
| 703 |
|
|
; CALL wait_for_the_ack
|
| 704 |
|
|
;JUMP Z,data_available_on_wb_master
|
| 705 |
|
|
|
| 706 |
|
|
wait_for_the_ack:
|
| 707 |
|
|
;
|
| 708 |
|
|
; CONTROL_WB_IN_MASTER -> TMP (s6)
|
| 709 |
|
|
;
|
| 710 |
|
|
INPUT sF,CONTROL_WB_IN_MASTER
|
| 711 |
|
|
;
|
| 712 |
|
|
AND sF,ACK_I_MASTER
|
| 713 |
|
|
JUMP Z,wait_for_the_ack
|
| 714 |
|
|
|
| 715 |
|
|
data_available_on_wb_master:
|
| 716 |
|
|
; This part is not necessary in write operations
|
| 717 |
|
|
; DATA_WB_IN_7_0_MASTER -> (sD) data[7:0] WB MASTER
|
| 718 |
|
|
; DATA_WB_IN_15_8_MASTER -> (sE) data[15:8] WB MASTER
|
| 719 |
|
|
INPUT sD,DATA_WB_IN_7_0_MASTER
|
| 720 |
|
|
INPUT sE,DATA_WB_IN_15_8_MASTER
|
| 721 |
|
|
; DISABLE RD/WR OPERATION REQUEST
|
| 722 |
|
|
LOAD sF,00
|
| 723 |
|
|
OUTPUT sF,CONTROL_WB_OUT_MASTER
|
| 724 |
|
|
RETURN
|
| 725 |
|
|
|
| 726 |
|
|
put_error_code:
|
| 727 |
|
|
LOAD sF,ERROR
|
| 728 |
|
|
OUTPUT sF,CONTROL_WB_OUT_SLAVE
|
| 729 |
|
|
JUMP put_error_code
|
| 730 |
|
|
|
| 731 |
|
|
interrupt:
|
| 732 |
|
|
RETURNI ENABLE
|
| 733 |
|
|
|
| 734 |
|
|
|
