Skip to navigation

Elite on the BBC Micro

Loader: COLD (6502SP version)

Name: COLD [View in context] Type: Subroutine Category: Loader Summary: Copy the recursive tokens and ship blueprints to their correct locations
.COLD \ First we copy the 4 pages of recursive tokens from F% \ to QQ18 LDA #LO(F%) \ Set V(1 0) = F% STA V LDA #HI(F%) STA V+1 LDA #LO(QQ18) \ Set SC(1 0) = QQ18 STA SC LDA #HI(QQ18) STA SC+1 LDX #4 \ Set X = 4 to act as a counter for copying 4 pages JSR mvblock \ Call mvblock to copy the recursive tokens \ And then we copy the &22 pages of ship blueprints from \ F% + &0400 to D% LDA #LO(F%) \ Set V(1 0) = F% + &0400 STA V LDA #HI(F%)+4 STA V+1 LDA #LO(D%) \ Set SC(1 0) = D% STA SC LDA #HI(D%) STA SC+1 LDX #&22 \ Set X = &22 to act as a counter for copying &22 pages \ Fall through into mvblock to copy the ship blueprints .mvblock LDY #0 \ Set Y = 0 to count through the bytes in each page .mvbllop LDA (V),Y \ Copy the Y-th byte of V(1 0) to the Y-th byte of STA (SC),Y \ SC(1 0) INY \ Increment the byte counter to point to the next byte BNE mvbllop \ Loop back to mvbllop until we have copied a whole page INC V+1 \ Increment the high byte of V(1 0) to point to the next \ page to copy from INC SC+1 \ Increment the high byte of SC(1 0) to point to the \ next page to copy into DEX \ Decrement the page counter in X BNE mvbllop \ Loop back to copy the next page until we have copied \ all of them RTS \ Return from the subroutine