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Add options to disable BSS clear on startup

This commit is contained in:
drmortalwombat 2024-08-23 20:31:17 +02:00
parent b48b8b836d
commit 8fbe96b9ac
2 changed files with 6 additions and 1 deletions
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2
README.md
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@ -141,6 +141,8 @@ A list of source files can be provided.
* -dNOLONG : no support for long in printf * -dNOLONG : no support for long in printf
* -dNOFLOAT : no float in printf * -dNOFLOAT : no float in printf
* -dHEAPCHECK : check heap allocate and free and jam if heap full or free out of range * -dHEAPCHECK : check heap allocate and free and jam if heap full or free out of range
* -dNOBSSCLEAR : don't clear BSS segment on startup
* -dNOZPCLEAR : don't clear zeropage BSS segment on startup
#### Supported target machines #### Supported target machines

5
include/crt.c
View File

@ -235,6 +235,7 @@ w0:
// Clear BSS Segment // Clear BSS Segment
#ifndef NOBSSCLEAR
lda #<BSSStart lda #<BSSStart
sta ip sta ip
lda #>BSSStart lda #>BSSStart
@ -264,7 +265,8 @@ l2: dey
sta (ip), y sta (ip), y
bne l2 bne l2
w2: w2:
#endif
#ifndef NOZPCLEAR
ldx #<ZeroStart ldx #<ZeroStart
cpx #<ZeroEnd cpx #<ZeroEnd
beq w3 beq w3
@ -273,6 +275,7 @@ l3: sta $00, x
cpx #<ZeroEnd cpx #<ZeroEnd
bne l3 bne l3
w3: w3:
#endif
lda #<StackEnd - 2 lda #<StackEnd - 2
sta sp sta sp
lda #>StackEnd - 2 lda #>StackEnd - 2