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57 lines
1.6 KiB
ArmAsm
57 lines
1.6 KiB
ArmAsm
;
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; Marco van den Heuvel, 2018-04-30
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;
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; unsigned char __fastcall__ set_turbomaster_speed (unsigned char speed);
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;
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;/* Set the speed of the Turbo Master cartridge, using SPEED_SLOW will switch to
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; * 1 Mhz mode, SPEED_4X or SPEED_FAST will switch to 4 Mhz mode.
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; *
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; * Note that any value higher or equal to SPEED_4X will switch to 4 Mhz mode,
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; * any value lower than SPEED_4X will switch to 1 Mhz mode.
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; *
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; * This function will return the actual speed the CPU is at after trying
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; * to set the requested speed, if the speed is different it might indicate
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; * that the hardware switch has locked the speed.
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; *
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; * This function does not check for the presence of a Turbo Master cartridge,
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; * make sure you use 'detect_turbomaster();' before using.
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; */
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; unsigned char get_turbomaster_speed (void);
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;
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;/* Get the speed of the Turbo Master cartridge.
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; *
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; * Possible return values:
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; * SPEED_SLOW : 1 Mhz mode
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; * SPEED_4X : 4 Mhz mode
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; *
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; * This function does not check for the presence of a Turbo Master cartridge,
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; * make sure you use 'detect_turbomaster();' before using.
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; */
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.export _set_turbomaster_speed
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.export _get_turbomaster_speed
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.include "accelerator.inc"
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_set_turbomaster_speed:
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tay
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lda TURBOMASTER_SPEED_REG
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asl
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cpy #SPEED_4X
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ror
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store_speed:
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sta TURBOMASTER_SPEED_REG
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_get_turbomaster_speed:
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ldx #$00
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lda TURBOMASTER_SPEED_REG
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and #$80
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beq is_slow_speed
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is_high_speed:
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lda #SPEED_4X
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is_slow_speed:
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rts
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