The SKIP instruction causes the Copper to skip the next instruction if the video beam counters are equal to or greater than the value given in the instruction. The contents of the SKIP instruction's words are shown below. They are identical to the WAIT instruction, except that bit 0 of the second instruction word is a 1 to identify this as a SKIP instruction. FIRST SKIP INSTRUCTION WORD (IR1) --------------------------------- Bit 0 Always set to 1. Bits 15 - 8 Vertical position (called VP). Bits 7 - 1 Horizontal position (called HP). Skip if the beam counter is equal to or greater than these combined bits (bits 15 through 1). SECOND SKIP INSTRUCTION WORD (IR2) ---------------------------------- Bit 0 Always set to 1. Bit 15 The blitter-finished-disable bit . (See "Using the Copper with the Blitter" below.) Bits 14 - 8 Vertical position compare enable bits (called VE). Bits 7 - 1 Horizontal position compare enable bits (called HE). The notes about horizontal and vertical beam position found in the discussion of the WAIT instruction apply also to the SKIP instruction. The following example SKIP instruction skips the instruction following it if VP ( vertical beam position ) is greater than or equal to 100 ($64). DC.W $6401,$FF01 ;If VP >= 100, ; skip next instruction (ignore HP)
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