diff options
Diffstat (limited to 'pal.S')
| -rw-r--r-- | pal.S | 13 |
1 files changed, 9 insertions, 4 deletions
@@ -566,6 +566,8 @@ ENDFN CallPal_Cserve_Cont * r17 (a1) = New PC * r18 (a2) = New PCB * r19 (a3) = New VptPtr + * r20 (a4) = New Procedure Value (to place into $27) + * (Non-standard; See note below.) * * OUTPUT PARAMETERS: * @@ -574,11 +576,14 @@ ENDFN CallPal_Cserve_Cont * 1 - Unknown PALcode variant * 2 - Known PALcode variant, but PALcode not loaded * - * r26 (ra) = r27 (pv) = New PC + * r26 (ra) = New PC + * r27 (pv) = From r20 * Note that this is non-architected, but is relied on by * the usage of SwpPal within our own console code in order - * to simplify its use within C code. - * + * to simplify its use within C code. We can get away with + * the extra non-standard argument (in $20) because as + * architected, all registers except SP and R0 are + * UNPREDICTABLE; therefore private internal usage is fine. */ ORG_CALL_PAL_PRIV(0x0A) CallPal_SwpPal: @@ -624,7 +629,7 @@ CallPal_SwpPal_Cont: mtpr $31, qemu_tbia // Flush TLB for new PTBR mov a1, $26 - mov a1, $27 + mov a4, $27 hw_ret (a1) ENDFN CallPal_SwpPal_Cont .previous |