moved most of the CLR and NEW commands to Mega65 extra ROM segment

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FeralChild64 committed 2020-02-26 22:36:08 +01:00
1 parent d1bc38694d
commit 4a510d78fd
6 files changed
+108 -81

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// #LAYOUT# STD * #TAKE
// #LAYOUT# * BASIC_0 #TAKE
// #LAYOUT# * * #IGNORE
cmd_clr:
jsr basic_do_clr
// CLR command does not stop execution
// (Cconfirmed on a c64)
jmp basic_execute_statement
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@@ -4,81 +4,9 @@
cmd_new:
jsr basic_do_new
// NEW command terminates execution
// (Confirmed on a C64)
jmp basic_main_loop
cmd_clr:
jsr basic_do_clr
// CLR command does not stop execution
// (Cconfirmed on a c64)
jmp basic_execute_statement
basic_do_new:
// Setup pointers to memory storage XXX should depend on text start vector
lda #<$0801
sta TXTTAB+0
lda #>$0801
sta TXTTAB+1
sta VARTAB+1
lda #<$0803
sta VARTAB+0
// Zero line pointer
// XXX - We should also zero $0800, i.e., TXTTAB - 1
ldy #$00
tya
sta (TXTTAB),y
iny
sta (TXTTAB),y
// Get top of memory.
// If a cart is present, then it is $7FFF,
// if not, then it is $F7FF, since we support having
// programs and variables under ROM.
// i.e., we support 56KB RAM for BASIC, keeping some space
// free for some optimisation structures, e.g., FOR/NEXT loop
// records (without them going on the stack), GOSUB stack
// (same story), expression value cache?
sec // Read, not write value
jsr JMEMTOP
cpx #$80
beq !+
#if CONFIG_MEMORY_MODEL_60K
lda #>$F7FF
#else // CONFIG_MEMORY_MODEL_38K
lda #>$A000
#endif
.byte $2C
!:
#if CONFIG_MEMORY_MODEL_60K
lda #>$F7FF
#else // CONFIG_MEMORY_MODEL_38K
lda #>$A000
#endif
sta MEMSIZ+1
sta FRETOP+1
#if CONFIG_MEMORY_MODEL_60K
lda #<$F7FF
#else // CONFIG_MEMORY_MODEL_38K
lda #<$A000
#endif
sta MEMSIZ+0
sta FRETOP+0
// FALL THROUGH
basic_do_clr:
// Clear variables, arrays and strings
lda VARTAB+0
sta ARYTAB+0
sta STREND+0
lda VARTAB+1
sta ARYTAB+1
sta STREND+1
rts