diff --git a/asm/registers.asm b/asm/registers.asm
index 4420cc4..bab14f0 100644
--- a/asm/registers.asm
+++ b/asm/registers.asm
@@ -169,4 +169,16 @@
 .constant SBUS_EPL_IP, %0xE800b
 .constant SBUS_EPL_IM, %0xE800c
 
-.constant PM_CLKOBS_CTRL, %0xE8012
\ No newline at end of file
+.constant PM_CLKOBS_CTRL, %0xE8012
+
+; These require offsets to be accessed
+.constant PCIE_PF_BASE, %0x100000
+.constant PCIE_IB, PCIE_PF_BASE +0x13002
+.constant PCIE_SERDES_CTRL_0, PCIE_PF_BASE +0x19010
+.constant PCIE_SERDES_CTRL_1, PCIE_SERDES_CTRL_0 +2
+.constant PCIE_SERDES_CTRL_2, PCIE_SERDES_CTRL_1 +2
+.constant PCIE_SERDES_CTRL_3, PCIE_SERDES_CTRL_2 +2
+.constant PCIE_SERDES_CTRL_4, PCIE_SERDES_CTRL_3 +2
+.constant PCIE_SERDES_CTRL_5, PCIE_SERDES_CTRL_4 +2
+.constant PCIE_SERDES_CTRL_6, PCIE_SERDES_CTRL_5 +2
+.constant PCIE_SERDES_CTRL_7, PCIE_SERDES_CTRL_6 +2
\ No newline at end of file
diff --git a/asm/stdlib.asm b/asm/stdlib.asm
index 102e59b..e38067e 100644
--- a/asm/stdlib.asm
+++ b/asm/stdlib.asm
@@ -13,13 +13,21 @@
 .constant P1                              std_PARAMETER_1
 
 ; These are offset registers to be called with <OP>~3 to access stack parameters
-.constant P2                              %1, +1 ; Equivalent to same address in POPP <Reg>, 1
-.constant P3                              %1, +2 ; Equivalent to same address in POPP <Reg>, 2
-.constant P4                              %1, +3 ; Equivalent to same address in POPP <Reg>, 3
-.constant P5                              %1, +4 ; Equivalent to same address in POPP <Reg>, 4
-.constant P6                              %1, +5 ; Equivalent to same address in POPP <Reg>, 5
-.constant P7                              %1, +6 ; Equivalent to same address in POPP <Reg>, 6
-.constant P8                              %1, +7 ; Equivalent to same address in POPP <Reg>, 7
+.constant P2                              %1, +1  ; Equivalent to same address in POPP <Reg>, 1
+.constant P3                              %1, +2  ; Equivalent to same address in POPP <Reg>, 2
+.constant P4                              %1, +3  ; Equivalent to same address in POPP <Reg>, 3
+.constant P5                              %1, +4  ; Equivalent to same address in POPP <Reg>, 4
+.constant P6                              %1, +5  ; Equivalent to same address in POPP <Reg>, 5
+.constant P7                              %1, +6  ; Equivalent to same address in POPP <Reg>, 6
+.constant P8                              %1, +7  ; Equivalent to same address in POPP <Reg>, 7
+.constant P9                              %1, +8  ; Equivalent to same address in POPP <Reg>, 8
+.constant P10                             %1, +9  ; Equivalent to same address in POPP <Reg>, 9
+.constant P11                             %1, +10 ; Equivalent to same address in POPP <Reg>, 10
+.constant P12                             %1, +11 ; Equivalent to same address in POPP <Reg>, 11
+.constant P13                             %1, +12 ; Equivalent to same address in POPP <Reg>, 12
+.constant P14                             %1, +13 ; Equivalent to same address in POPP <Reg>, 13
+.constant P15                             %1, +14 ; Equivalent to same address in POPP <Reg>, 14
+.constant P16                             %1, +15 ; Equivalent to same address in POPP <Reg>, 15
 
 ; Ephemeral registers to be used within functions. These values may not be kept when calling other functions. They can be used when returning values if necessary.
 ; Some std functions might restore these values.