Routines
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7BFB: Move a character looking for ERIC from the midstride position
Used by the routine at F78E. The address of this interruptible subcommand routine is also placed into bytes 0x69 and 0x6A of a character's buffer by the routine at 7C18. It moves ERIC's chaser from the midstride position.
Input
H Number of the character looking for ERIC (0xA1, 0xA3-0xA6)
7BFB LD L,$69 Replace the address of this routine in bytes 0x69 and 0x6A of the character's buffer (if present) with that of 7BA0
7BFD LD (HL),$A0
7BFF CALL $6214 Update the SRB for the character's current location
7C02 LD L,$6C D=character's new y-coordinate (adjusted by the value in byte 0x6C of his buffer, placed there by the routine at 7C18)
7C04 LD B,A
7C05 LD A,D
7C06 ADD A,(HL)
7C07 LD D,A
7C08 DEC L E=character's new x-coordinate (adjusted by the value in byte 0x6B of his buffer, placed there by the routine at 7C18)
7C09 LD A,E
7C0A ADD A,(HL)
7C0B LD E,A
The character's post-midstride coordinates have been calculated; now we consider his post-midstride animatory state. Usually, a character's animatory state is incremented as he moves to or from the midstride position, which makes his walking animation cycle through phases 1, 2, 3 and 4. However, the next section of code - unlike its counterpart in the routine at 7C18, which moves ERIC's chaser to the midstride position - decrements the animatory state if the character is moving leftwards, and increments it if the character is moving rightwards. So when a character is moving leftwards while chasing ERIC, his walking animation will cycle through phases 1 and 2 only, or 3 and 4 only. This is a bug.
7C0C LD A,(HL) A=x-coordinate increment (-1 or +1)
7C0D ADD A,B Add this to the character's current animatory state
7C0E AND $03 Now C holds the new walking phase bits
7C10 LD C,A
7C11 LD A,B A=character's current animatory state
7C12 AND $FC Clear the walking phase bits (bits 0 and 1)
7C14 ADD A,C Set the walking phase to 1 (C=0) or 3 (C=2)
7C15 JP $61B0 Update the character's animatory state and location and update the SRB
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