diff options
| -rw-r--r-- | cf-code/cf-fsi-fw.S | 7 |
1 files changed, 5 insertions, 2 deletions
diff --git a/cf-code/cf-fsi-fw.S b/cf-code/cf-fsi-fw.S index 32f6aa8..60affc7 100644 --- a/cf-code/cf-fsi-fw.S +++ b/cf-code/cf-fsi-fw.S @@ -76,8 +76,6 @@ .endm /* clock_out_bit reg: Clock out bit 31 of reg */ - /* XXX TODO: only write to GPIO if value changes */ - /* XXX TODO: can probably optimize further using shifts & logical ops rather than branches */ .macro clock_out_bit reg:req btst.l #31,\reg beq 98f @@ -87,6 +85,11 @@ 98: bclr.l #DATA_GPIO_BIT,%DDAT trace #TR_CLKOBIT0 99: + /* If data and clock GPIO share the same register, such as on + * Romulus, the write done by clock_toggle will set the new data + * value along with the low clock edge. Thus we don't need to + * set it here, thus saving a PCLK + */ #if DATA_GPIO_REG != CLOCK_GPIO_REG move.l %DDAT,%a4@(0) #endif |
